How likely do you think it is that congress sent a letter that references "the enclosed subpoena" without enclosing a subpoena?
Will you assume that a subpoena was enclosed with the letter if a federal judge rules on it without any mention of whether or not the actual document was served?
I don't care about your totally arbitrary statistical projections. A subpoena is a legal document, and a matter of public record. I maintain it does not exist, and have not reviewed any document that would have force of law. Your premise seems to be that the subpoena exists, you just can't find it, or refuse to look for it. I am not sure how I am supposed to prove the non-existence of something to you, but you can certainly prove the existence of the subpoena to me (if it actually existed). You have the burden of proof. Just keep looking, you are sure of yourself, you will find it eventually.... right?