Unauthorized Billing.

It really "chaps my hide" when companies do this.  I have a classmates account as well and I occasionally activate it to the gold level.  So far (keeps fingers crossed) I have seen no unauthorized charges.

The first thing I would do is call your credit card company and see if they will block any further charges from classmates.

If that doesn't work I would call or email classmates, repeatedly,  and give them a piece of your mind.  What's the worst they can do, hang up on you or close your account.

If that doesn't work you might need to cancel the credit card.  It's a shame we need to resort to these measures but in a world of electronic transactions where PG&E can cash a check I mailed them made out to American Express you just can't be too careful.  But I digress.... 

In most cases the absolute best way to deal with these things is to use a one time use credit card number.  Most credit card companies have these available now on their web sites.  By doing this you will need to use a new one time number when the account expires but there is NO way they can continue to bill it after it's used.

You're best first bet is your credit card company.  call them and explain the problem.  It's their job to help you (regardless of what they may say).  Good luck.

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