USPS delivered an international package to the wrong address while it was supposed to be held, and won't offer refund because it was international package. How can i get my money back?

I recently ordered a $500 item from ukraine. Ukrposhta is not responding to my emails, and USPS is saying that ukrposhta must reimburse me. Unfortunately, ukrposhta has marked the package as successfully delivered and won't reimburse.

USPS delivered the package while i had a mail hold request, AND they delivered it to the wrong address. they literally did everything wrong. i just want my money back. what can i do?