We recently reported that there seems to be a widespread data breach as a lot of cardholders are seeing unauthorized/fraudulent charges on their cards. If you haven’t already checked your cards for these transactions it’s strongly recommended that you do. Most card issuers are cancelling the current cards, issuing a new card and then refunding the unauthorized charges.
Unfortunately it seems that American Express is not doing the last bit and claiming that these charges are the responsibility of the cardholder (1, 2, 3, 4). If you dispute the charge a second time, American Express is refunding the charge (1). I suspect this will be eventually fixed and refunds will be offered after the first dispute once American Express realizes how widespread this problem is.