where are you trying to sign into ?
really no need to cancel it. You don't pay for it and it shouldnt bother you any.
make a new account if you want to use it.
otherwise cancelling it would be as difficult as logging in. You cant cancel it if you cant log into it.
ok if they are taking stuff from your bank account you must have set it up that way at some point.
if you know anything about it even the skype name we might be able to get into it
the other way to do it is to just call the number on the back of the credit card and dispute the charges. The credit card company will refund the money to your account immediately and possibly issue you a new credit card number so that they can not take any more out in the future