If it is like other sites (Gameknot) you may need to make sure your account is closed correctly or they may deduct money from you'd account still. As I recall at GK there as an option buried in with all the information. I am sure there is some sort of Sales Support contact.
Not hard. You can lose your membership renewal here. Home>Account>Big Yellow box. To cancel altogether, same page but just under the blue Facebook box. Sorry it didn't work out.
HOW CAN I RESIGN AS A MEMBER