In short, you can report them to Visa or MasterCard and (hopefully) corrective action will be taken. Here’s how to get in touch with the two companies…
Reporting Visa credit card violations
Perhaps the easiest way to get in touch with Visa is to call them at 1-800-VISA-911. Alternatively, you can call the number on the back of your card.
If you would prefer to send a written complaint, you can address it to:
Visa U.S.A. Inc.
P.O. Box 194607
San Francisco, CA 94119-4607
You might also be able to register your complaint online through your card issuer’s website, but Visa doesn’t have a centralized way of doing this.
Reporting MasterCard credit card violations
Once again, you can call in your complaint to 1-800-MASTERCARD, or you can call the number on the back of your card.
Alternatively, you can register your complaint online via the MasterCard Merchant Violations page. You’ll be asked for your name and address, details about the merchant, and the nature of the problem. There is also space for freeform comments.
Have you ever reported a merchant?
Have you ever reported a merchant for violating the terms of their credit card agreement? Perhaps they required ID, attempted to add a surcharge to your purchase, or tried to enforce a minimum purchase amount.
If so, please share your experience in the comments.