Alibris  -  product never received

On 12/23/09, I placed an online order for a book and received confirmation of my order(#[protected]). I was charged for the full amount $62.24 but never received the book. I tried to contact the seller several times and, on 4/13/2010, received an email letting me know that another copy would be shipped. However, I have never received the package. Alibris is telling me that, because the issue is so "old", it's ok for them to keep $62 (I checked I was charged but not reimbursed)... Isn't that considered theft?