I believe that the buyer should have been there, or made arrangements for someone to be there. I know I do if I am receiving a package. I have even talked to my delivery person, and they know to take it to a local store, for me to pick up later. If the package was not signed for, and left on the doorstep, this is out of your hands. You should not have to pay.

As for the USPS shipping... I do not know due to the snake not being alive. Depending on the heat, 2 days can make for a very smelly package.