Since the place of purchase is showing as New York on your statement, I would presume that this would be treated as a domestic charge. I still feel that Mastercard regs would side with the merchant in your case, they did disclose a fee, and you chose to continue with the transaction knowing that a fee would be charged should you cancel. The fact that you did not know the specific fee will likely not matter much in the chargeback arbitration process. The merchant's bank rep will probably argue that you should have inquired about the fee before completing the transaction. I dont mean to sound harsh, but in my experience, "I didn't know" is often not enough to make a chargeback stick. I have had a few 'fights' between the card issuer (the bank that your card is with) and the aquirer (the merchant's bank that processes thier credit card transactions) can get quite ugly! You can certainly try disputing, and hopefully the person that handles your case will be willing to get creative to fight for you. The first step would be for you to contact the merchant, and request that they charge a smaller fee / issue more credit. Document your attempt to work with the merchant, and provide it to your credit card company. If you cannot reach the merchant, then make sure to include an explanation of how you attempted to contact the merchant.