My kid purchased something with my credit card without my permission. Do I have to pay for it?
Once you have authorized someone else to use your account, you are responsible for charges made by that person until you notify the card issuer in writing that the person is no longer authorized to use your credit card account.
If you have not done so, you are responsible for the charges the previously authorized person made. If you have notified the card issuer, you should submit a billing dispute for any charges made after your notice was delivered.