pshea - 6:31 pm on Sep 8, 2007 (gmt 0)
I have had chargebacks reversed after presenting delivery documentation. Not with American Express, of course. You can contact the postmaster of the delivering PO; he/she will likely speak to the carrier who made the delivery and offer you further information about the package. I have done this several times in the past and have always found the folks at the local PO very helpful.