"If there’s ever an unauthorized charge on your credit card, your credit card issuer is liable for 100% of the charge – not you.
Just call your issuer, identify the unauthorized charge, and it becomes their responsibility to deal with the merchant and investigate the fraud. In the meantime, the issuer will pay off the fraudulent charge.
That’s why credit cards are great to use online, or when travelling. Even if your card gets stolen, hacked, or used by the busboy from a restaurant in China, it’s the issuer’s problem, not yours."