What can i do about continued charges on closed account?

What can i do about a company that continues to try to charge my card even after numerous phone calls to them requesting them to stop. The charge that keeps coming through is not owed to this company in any way shape or form, i took part in a 2 week free trial on a game website, and cancelled the membership before the 2 weeks were up. I noticed these charges not too long after i had canceled the membership, and went back to the site and clicked a button that said remove my credit card info, and then got a response saying that it had been removed, but they still attempted to charge my card after that. So i then called and the representative i spoke to said that clicking that does not really remove my info from their system, just in case i wanted to come back to being a member, and then reassured me that my card info was personally removed by him on 6/8/11. i have since seen charge attempts on 6/10 and 6/12. Any ideas on what i can do about this from a legal standpoint?