DrBob; sorry to here of your situation. I had one a few years back. I filed a claim to the Post Office and I think they sent a postal inspector to investigate. The situation was rectified lightning fast. Apparently a U.S. Postal Inspector has some authority.

I now use a debit card or postal money order even if I have to purchase several to get the amount needed.

Good Luck and please let us know how things turn out.