Seems I spoke too soon, USPS made another attempt (After saying they were returning it!) and it went through, and I also received an email confirmation that they received it.

Cheers.

(also, as an aside, can the 'doxing'-ish stuff go someplace else unless it's really obviously interesting and relevant? it's making it hard to track actual news in the thread. If you find out one of HF's executives was convicted of fraud or something, thats news— but the rest of the details are only useful in so far as they may help people track them down in future lawsuits if needed... it doesn't rise to the level of news.)