I posted this in the Questions forum, and someone suggested I post it in the USP one to get some advice. Here's the link:

http://www.paperbackswap.com/forum/view_topic.php?t=86661

Natalie

Sherry's advice was correct in the Questions forum, Natalie. The sender should take the book back to the PO and tell them that the address is correct and no forwarding is needed. They should re-mail it to you with no further expense to the sender. Perhaps she can take an email message from you with your name and address printed on it to show them that it is correct as addressed.

And this is one of those situations that doesn't have a satisfactory explanation. We'll probably never know what happened.

On a side note, you sure seem to be having a run of bad luck when it comes to all things postal these last couple of weeks, Natalie! I'll sprinkle some of my magic postal pixie dust your way to see if that helps you out a little bit!!