There are a few concerns here.
Does the document you describe actually have the properties you describe? Indeed, can any document at all have them?
Should you believe in the specific claims of the statements you're describing, supposing that it actually does have the properties you describe?
Should you in any case do A, B, C and refrain from X, Y, Z?
#1. Concerning your five properties
There has historically been some controversy around the sort of properties that you describe for the statements you're describing.
On the supernatural and the everyday world
Property #2 is the one which immediately strikes me as problematic on its face. On what basis can any statement make claims that lie outside of the domain of logic? If it makes claims to which logic does not apply, how can I possibly reason about it?
Perhaps you mean that it makes claims which lie outside of any possibility of logical justification. But then what you are asking is whether you are rationally justified in believing in a statement which is defined to be logically unjustifiable. To answer this question, you must determine what grounds you have for rationally believing in something, despite the idea lacking any logical justification. Pascal's Wager is an argument that you should believe such a statement, simply to optimize your experiences after death; or in short that you should heed the possibility of an unproven authority, to avoid the threat that this authority could make things uncomfortable for you if you do not.
As to the idea that anything can lay outside of the domain of mathematics: this depends on what you think mathematics consists of. If you think that mathematics is a platonically defined subject, perhaps the phrase could mean something; but how would you determine that something was "beyond math"? Presumably it would be difficult to measure deviation from mathematical sensibility, because that would again suggest that it is at least somewhat tractible by mathematical technique. On the other hand, if you believe that mathematics is the result of human activity, this means that it is extensible — but perhaps only to certain limits. With topics such a computational complexity theory, we can come to grips with the notion that there are types of mathematical activity which, while in principle possible and in a sense 'platonically' well-defined, is extremely time-consuming in practise (e.g. there are problems whose resolution would require an amount of time similar to the age of the observable universe).
However, the notion of "supernatural" is the most problematic one. What does it mean for something to be "beyond nature"? What, indeed, is 'nature' if not the physical universe — and what does it mean for something not to be 'physical', or to not be subject to "the laws of physics"? Again, the subject of physics may be construed to be the activity of people to find out how the universe works: and there is no real way to divide it into 'miraculous' and 'non-miraculous' domains: there is simply the way that things are, and we may be forced to re-evaluate our notions of how things work when we encounter exotic phenomena. David Hume is an important European philosopher to raise the question of expectation and accumulation of evidence, who would criticise the notion of miracles. While taken from his treatise on the notion of causation, it applies equally well to any notion of what "the physical" could consist of: "[I]t is only experience which teaches us the nature and bounds of cause and effect, and enables us to infer the existence of one object from that of another."
As to your specific claim that the subject is 'supernatural' because it concerns "the end of the whole universe": just because the topic concerns the whole universe, does not put it outside of rational enquiry. (Indeed, we have a branch of observation science which does just this: it's cosmology.)
Finally, something which strikes me is the constrast between your notion of a supernatural topic, but which somehow meets your criterion #3. How can something both be supernatural and beyond logic, and also have a basis in the daily sensible real world? There's also a problem with judging that the statement "he who can create the universe can also bring me back to life" has to do with your everyday experience: if you had very much experience with the creator of the universe or with people being brought back to life from death, you might not be so concerned with suddenly discovering this piece of paper you're worried about. Indeed, at issue is exactly the question of believing it despite the fact that you have no experience with this supposed creator of the universe: do you believe that the piece of paper could only have been written by the a superhuman being?
Concerning aesthetic appeal
I think it must be very difficult to evaluate whether or not something has a super-human source (if not a supernatural source) on aesthetics alone. It is not entirely apparent how to measure aesthetics at all, for example, except by popularity contest.
Consider how aesthetics are formed. There is likely to be some more-or-less universal component to human aesthetics: people seem to enjoy sweet food, music with a strong rhythm, vivid colours, a somewhat structured environment, and signs of healthy animal and plant life. There are reasons to suppose that some of these are part of our genetic heritage, as a result of where humanity arose, behaviours or abilities which contributed positively towards survival, and so forth. But a lot of aesthetics are inculcated culturally — so much so that many people do not at first enjoy the cuisine, the music, the clothing, etc. of other cultures.
So determining how exactly to measure the superlative expressive qualities of a statement is a bit tricky. Does the fact that it isn't even intelligible to anyone who does not speak the language pose a problem, for example? If it is expressed poetically, is there anything deeply rooted in human nature which dictates the poetic form it has?
Perhaps one might concede that, at least for a specific culture speaking a specific language, the aesthetic form of the statement might represent a quality of craft which would be hard to reproduce — perhaps because of some deeply patterned metrical device, multilayered rhyming structure, an improbably successful and natural alliterative scheme, or simply a quite reasonable but well-sustained quality over a very long piece of writing. If we suppose that the style of poetry can be defined well enough that you can describe a mathematical structure describing the "space of excellent poetry", then perhaps you might be able to argue on computational grounds that it was not produced by a human, if the problem of generating long pieces of similarly excellent poetry is a problem which is computationally intractible. It is not clear to me how else one might rigorously argue that anything which is comprehensible to humans could not possibly have been produced by a human.
This, of course, does not address whether the superhuman being was actually the creator of the universe, or has the power to carry out the ultimatum which it has issued, but it would certainly be interesting to learn that there were convincingly superhuman entities out there who are interested in meddling with human affairs.
#2. Concerning whether or not you should believe in a document with the properties you describe
So: suppose that you actually do encounter a document, whose structure gives strong evidence that it was written by a superhuman intelligence, which makes claims of great power, it does not contradict anything that you know about the world, and it seems internally consistent. Should you believe that it was written by the particular superhuman intelligence that it claims? Should you believe that the superhuman author actually will reward or punish you according to what it says? This is a difficult question, because we know very little of the motivations of the superhuman intelligences.
In fact, on a less grandiose scale, we can consider a similar question of motivation for a parent might write to them in a note left to a child:
The parent can tell the child of a punishment or reward for their future behaviour (e.g. doing some chores);
The parent claims that they are the reason why the child even exists (they are their creator);
The child has ample opportunity to observe the physical and economic power of the parent, which to a child is enormous;
The parent can express themselves in very clear handwriting with very few spelling errors and a large vocabulary which the child understands but could not easily write themselves;
The child cares about the rewards or punishments.
How is the child to know whether the note was actually written by the parent, and not instead by an older sibling trying to get out of their chores themselves?
We understand the motivations of a possibly deceptive sibling, and they may also have superior spelling, handwriting, and vocabulary to the younger child. The motivation of the parents, of course, is also to avoid having to do the chores themselves, but usually because they already have a lot of other things that they have to do.
There is a difference, of course, in that good parents never give extreme punishments. After all, aside from dealing with everyday life (as in the doing of chores), they are interested in the welfare of their children, and want them to thrive. Parents may sometimes bribe their children with minor rewards for eating their vegetables, or threaten them with minor punishments; but this is because the parents want the children to eat their vegetables in order to be healthy, and would not consistently and knowingly punish their children with anything which would make them less healthy.
A good parent, in fact, should not even threaten an extreme punishment for a lapse in behaviour, because it is a violation of the trust between the child and the parent. If the child believes that the parent doesn't have their best insterests at heart, they are led to believe that they are in essence a captive of a tyrant, which will stunt their emotional development. And even if indeed the parent never intends to carry out the harsh punishment, it shows that they are willing to put the child through a good deal of emotional anxiety for petty things.
What motivations do superhuman intelligences have, when they exhort us to do certain things or avoid other things? The problem is that aside from cryptic writings copied down by humans, we don't have a lot of experience with superhuman intelligences, and so we don't have a good basis for evaluating whether claims about them are probable or not. But here we have assumed for the sake of argument that a superhuman intelligence has indeed written this document. Perhaps, then, the fact that the document leaves any doubt in you indicates that however superhuman the author was, they were not actually all-powerful; otherwise they could present you with a claim so convincing that there is no possibility of doubt in your mind.
But perhaps it's just a question of the limitations of the document: it might be simply impossible (even for a superhuman intelligence) to write such an overwhelmingly compelling document. If you could only find some way to contact the superhuman intelligence, you could have a dialogue in which you can ask for clarification — if not of the things that they want, at least the reasons why they want you to do them, what its motivations are.
Again, if there isn't much trace of superhuman intelligences in daily life, contacting the author might be difficult, but it seems like the most practical recourse. Perhaps there are people who have also tried contacting them; you could ask them for their advice in contacting them, and perhaps as a starting point find out if they seem to agree on the sorts of things that the author would like.
(On a personal note, I can tell you that in the past I tried in earnest to contact the author of the Qu'ran, having been a fan of his earlier works. I'm not convinced that I was successful. Perhaps you will have better luck.)
#3. Concerning ethics
Of course, there is a question completely aside from these concerns. Should you do A, B, C and refrain from X, Y, Z?
If the message from the superhuman author is true, then you should; but this is only a sufficient reason to conform to a particular code of ethics, not a necessary reason. You could choose to adopt that code of ethics anyway; perhaps it appeals to you.
The appeal of a code of ethics is an interesting one: we are back at aesthetics. Does the code of ethics itself have a strong aesthetic appeal to you? How would you go about evaluating a code of ethics, and on what grounds? Kant's notion of the categorical imperative could arguably be said to be an aesthetically motivated approach to evaluating ethical behaviour: it is simple enough to forumlate, and inherently applies the notion of symmetry, which is a fairly common feature of aesthetics.
Ultimately, if you are in doubt as to the existence or motivations of a superhuman author of some moral commandment, you are left with deciding for yourself what your moral code is — either for lack of a better source, or to judge how much your priorities are aligned with the so-called superhuman moralist (so to decide whether to be a collaborator with them). The behaviour of others can be used to inform your ideas of what is ethically productive, but then this still depends on what you think the objective of a well-lived life is: to contribute to your community? To have a thriving family? To live according to a well-chosen code regardless of the consequences?
In the end, it basically comes down to this: will you live for yourself, and as well as possible, or will do you think it better to live your life according to a code of a person whose identity you cannot verify? You must at least decide, as part of your moral code, on what grounds you will be convinced of the existence of superhuman moralists based on their ability to write poetry; I would say that you should evaluate what you value in life, and then — among other things — choose whether or not to heed the document you describe on that basis.
