In order to get a chargeback for a charge that you did not authorize, you have to tell your credit card company that you specifically want a chargeback. Do not tell them that you are disputing the charge. If you do not use the term "chargeback" they will merely contact the vendor who will then advise that the charge is valid. Under Visa/MC rules, if you ask for a chargeback using that language they have to give it to you.
