Annoyed

I had an issue with a textbook I bought online-- the package arrived---
with delivery confirmation, but the back of the package was cut open,
and no textbook was inside. And, since the postal clerk did not mark
the mail, Without Contents, I'm having a hard time proving to the seller
(I bought the book on half.com) that I did not receive it. So far, I've
had to file a claim with the post office and I've sent a few emails to
the seller as well. I know it is not her fault, but she was paid on the
condition of me receiving the book. Since I never received it, I feel I
am owed a refund. Not only am I out the $53 I paid for the book, but
now I will have to pay another $100 to go buy a new book at the school
bookstore. This totally sucks! Hopefully they still have it in stock.
I don't want to fail this class and have it ruin my GPA! Also, this
class cost about 2grand. I think I will charge the textbook; I know
this is going to increase my balance, but I feel this is essential. I
could pay by cash but I'd rather not. I will make up for this next
paycheck.