I think you need to check your PURCHASE HISTORY. Did you buy anything or win any auctions? It will show there if you did. Is it on a different User ID account? If there is any chance someone else is bidding on your account, change your password now. But first go and look at the PH as far back as you can (only 2104 I think), including the Hidden ones.
Sellers set up their accounts to BLOCK anyone with 2 or more UNPAID ITEMS so that is what you are running into.
