Product: Credit card

I booked a trip on XXXX XXXX XXXX to sail from XXXX XXXX, 2015 through XXXX XXXX, 2015. My family and I waited in line for over 3 hours, by the time we arrived at the ticket counter we were hot, tired, and frustrated. We also had problems with our paperwork that added to the frustration of the boarding process. I was asked to give them a credit card for on board purchases, which I did, and also told them that the limit for my American Express card {$4500.00}. I then signed and finally we were able to board. During the cruise some purchases were made and signed for. However on XXXX XXXX there was {$2900.00} charged at the casino machines that day alone. Although some charges were made by us, I do not believe that the charges on the night of the fifth were made by me. I have reason to believe that I was drugged, robbed, and assaulted. That evening I recall playing the slot machines and sitting at the bar. The gentleman next to me was claiming to be a DEA agent, which surprised me because I 'm pretty sure that impersonating a government agent is a crime. He asked me my birth date and took my casino card so he could by me a drink. I did n't think anything of it at the time, but I noticed that the staff thought it was very funny. I went blank shortly after that, I do not even know how I got to my room. I did however wake up with a head wound and sore shoulder. I laid in bed the next day feeling worse than a typical hangover and sore, at this time I knew nothing of the charged from the night before. The following day before disembarking, I received the bill and was shocked. I noticed that the line for customer service was very long, and because of being short on time, I decided to leave and contact XXXX only to deal with very rude individuals. I then contacted my credit card on XXXX XXXX, 2015 telling them of my dispute of the {$2900.00} and my reasons why. They contacted XXXX only to receive the copy of the paper I signed before boarding the ship. They sided with the merchant. I called American Express the same day I received the letter and requested they reopen the dispute because of my concerns. On XXXX XXXX they send me a letter stating that they are still waiting to hear from XXXX and that they have 2 weeks to reply before they decide in my favor. I received an e-mail on XXXX XXXX telling me they had received a response from XXXX, and I received a letter today dated XXXX XXXX, they stating that they 're siding with XXXX because of the signed statement before departure. They answered none of the questions nor provided the requested proof of purchases. I think that by providing proof, it will confirm my belief of being XXXX and robbed. I also question the practice of American Express allowing a card member to go over his limit by almost {$1900.00}. This action on their part could have prevented the theft I believe occurred. They reported the total amount to credit agencies showing no dispute and now my credit has dropped XXXX points.Is this how disputes work? Yield to a merchant without any proof? No signature was required for the disputed amount, yet I had to sign for coffee, bingo, and daycare. They also have video cameras all over the place, so it should be no problem to confirm my suspicions. The gentleman at the bar posing as a agent could have been a ship worker, they could 've easily XXXX me since they bring open bottles to customers. Any help with this would be greatly appreciated. 

Thanks