Share your insights or perspective on the financial matter presented in the input.

Dispute credit card transaction with merchant or credit card company?
You should dispute the transaction with the credit card. Describe the story and attach the cash payment receipt, and dispute it as a duplicate charge. There will be no impact on your score, but if you don't have the cash receipt or any other proof of the alternative payment - it's your word against the merchant, and he has proof that you actually used your card there. So worst case - you just paid twice. If you dispute the charge and it is accepted - the merchant will pay a penalty. If it is not accepted - you may pay the penalty (on top of the original charge, depending on your credit card issuer - some charge for "frivolous" charge backs). It will take several more years for either the European merchants to learn how to deal with the US half-baked chip cards, or the American banks to start issue proper chip-and-PIN card as everywhere else. Either way, until then - if the merchant doesn't know how to handle signatures with the American credit cards - just don't use them. Pay cash. Given the controversy in the comments - my intention was not to say "no, don't talk to the merchant". From the description of the situation it didn't strike me as the merchant would even bother to consider the situation. A less than honest merchant knows that you have no leverage, and since you're a tourist and will probably not be returning there anyway - what's the worst you can do to them? A bad yelp review? You can definitely get in touch with the merchant and ask for a refund, but I would not expect much to come out from that.