Agree with Darth K'Trava that you probably got phished with the original e-mail. The reason your login/password didn't work is that you weren't really on eBay; you were on some phishing site that was harvesting logins/passwords.
I had someone list an auction using my ID. Went to Ebay and cancelled the auction AND changed my password. Not sure how the frell it happened. Then when I cancelled the auction, I got a <crap>load of spammy emails from various addys..... Annoying as hell.