If you haven't been listing, then someone has pirated your powerseller logo, hosted on AW, and is using it in their auctions....
You can always change the name of the image so it will no longer be accessible.
I would recommend, if you wish your account terminated, that you put that request in writing (keep a copy for yourself) and send it via certified mail to their corporate address with return receipt requested. Then, if any further charges are levied after that point, you can dispute them with your CC company.
