Good advice but keep this in mind. If you have an address you just contact
the postmaster in the zip code, or postal inspection service and they will run it down.
I had a person in Boston who dared me to get my money back, even wrote in his email
that "some dumb postal inspector" was too stupid to follow-up. Inside of a week after
sending the email & complaint to the postmaster I had my money returned with an apology.