HRoth - 11:54 pm on Apr 11, 2011 (gmt 0)
IME, sometimes some individual out there battens on your site and doesn't let go. I had a guy in Indonesia who tried for years to order using various stolen cards. Then it switched to some individual in Ghana who would even call me up. Could it be someone like that with you? Or maybe you have come to the attention of a particular group.