Report it as I don't think it's allowed to have two accounts simply for the reason you have come across. Should be an abuse@ebay sort of email adress to report it to, they can check the IP addresses of both accounts to see what is going on.
---------- Post added at 19:31 ---------- Previous post was at 19:27 ----------
http://pages.ebay.co.uk/help/policie...l-bidding.html might be what you need