Weight Watchers Weight Wachers online I only signed up for 3 months but since they had my credit card info. they keep billing me till now Internet

My name is Sheri,
I signed up with weightwatchers online program for 3 months special on May 2011. They still withdraw money from my credit card!  I called them and told them if I wanted to sign up for longer period of time, I wouldn't sign up inittially for 3 months. They said the expiration period is terminated and you did not cancel that is why you been billed.
I was heard that we should not give credit card info online to the merchants since we can't trust them. Please investigate this and do not let others become a victim of this fraud. My email address is: sheribien@wildmail.com
I am willing to become a member of a lawsuit if other vicitims decided to sue this company.