I had something similar happen one time. I used the 'ask seller a question' to email the seller. Basically I said "What's going on? I won this item from you in auction #_____ that ended on (date)".

I received an email/apology from the seller, who immediately ended the auction and sent the item out. Don't remember exactly what the story was...several people working together, someone didn't know the item had been sold and listed it again...or something like that. Mistakes do happen.

Hope your situation works out as well as mine did!