Product: Credit card or prepaid card

On XX/XX/XXXX, I went on vacation to XXXX. I brought my travel rewards credit card and my debit card. On XX/XX/XXXX, I missed my XXXX flight from the XXXX XXXX XXXX XXXX . The change flight fee was {$40.00}, I gave the attendant my credit card and it was denied several times, I then gave her my debit card and it was denied also. Fortunately all I had was {$40.00} in cash on me so I purchased the new ticket. Once I was at my gate I opened my Bank of America online banking app on my phone and noticed several erroneous and fraudulent charges to both my debit and credit card totaling over {$10000.00} from a merchant named " XXXX XXXX XXXX XXXX ''. The charges to my debit card were denied but 3 charges to the credit card totaling {$6800.00} were processing. I immediately called Bank of America to report the fraudulent charges. The bank associate I spoke to was very rude and told me that my chip was used for the purchase. I said that cant be because I never made those purchases and they are clearly fraudulent due to the nature of the charges. The only time I was without my card was when I went scuba diving a few days earlier. I asked why were these charges allowed on my credit card and rightfully denied for my debit card especially if they put me over my credit limit of {$5000.00}. I did not get an answer. I was told a temporary credit would be placed on my card while it was researched. 
A few days later I noticed that only two of the 3 fraudulent charges were credited. I called Bank of America to ask why and they explained the associate I spoke to the first time did not do all three as she should have. He added the third charge to the fraud claim and a few days later it was also credited. 
I believe I called on XX/XX/XXXX when I noticed the charges were back on my account. I received a letter after my call from Bank of America dated XX/XX/XXXX in the mail a few days later. The letter said were unable to approve your recent fraud claim '' for the reason of " - We confirmed your card was used for the charge ( s ). The chip was read, your PIN was entered, and/or you signed for the merchandise or service, which indicates you or someone you allowed to use your card was present. '' The charges were again added to my card. I called Bank of America as soon as I could and the associate told me that all claims that say the PIN/ signature were used are initially denied and when I contest, the claim is allowed to be investigated further. I asked what kind of investigating is done because I never used my card for those purchases. I said what if I go in a store to buy something and they charged me without my knowledge. I asked if I can get the merchants contact info but they did not have it. I said the charges look like they are for a dental service, I said I have dental insurance here, I would never go to XXXX for XXXX  service. The claim was escalated to be researched and the charges were again credited. The temporary credits were again issued to my card a few days later. 
In early XXXX of XXXX, I noticed the charges were again on my card. I called Bank of America immediately. The associate could not understand why I was charged the fee and told me that my claim was approved. She said she thought it was because the card number changed. The associate then issued a new credit card and transferred me to the claims center to fix the problem. The claim associate assured me that I would not have to pay a dime on the claim. I later received a letter from Bank of America dated XX/XX/XXXX stating the exact opposite of what I was told. The letter stated that the fraud claim was declined for the same reason of " - We confirmed your card was used for the charge ( s ). The chip was read, your PIN was entered, and/or you signed for the merchandise or service, which indicates you or someone you allowed to use your card was present. '' I hoped that this letter was a mistake as it was and still is not in my messages file of my Bank of America account as are all the others, A temporary credit was still on my account and I was assured that the claim was approved. 
I later received a letter from Bank of America dated XX/XX/XXXX stating the temporary credit of {$6800.00} while they conduct research. I was still hoping for the best. On XX/XX/XXXX when I checked my account, the {$6800.00} fraud dispute was again charged to my account. I called to complain and again I was told not to worry and it would be reviewed. But this time the charge remained. On XX/XX/XXXX I received two letters from Bank of America. The first letter read Good news your claim has been resolved. Were happy to let you know a credit ( s ) has been placed on your account. The second letter read unfortunately, were unable to approve your recent fraud claim. But this time two different reasons were given as to why my claim was denied, both lies. The first reason was - We confirmed statements were mailed to the address you provided for this claim and payments have been made on the account. An outright lie, I never received statements from XXXX, especially for a service I never received or purchased. That was my only time in XXXX and I stayed a week. So to say they mailed a statement and I paid is ridiculous. The second reason they gave was -After you submitted your claim, you later confirmed that the charge ( s ) was valid. More lies, I never have and never will confirm these charges that I did not make. 
I called the claims department and all they can tell me is they contacted the merchant. I asked if I can have the contact info and they said they do not have it. Ive been asking them since the beginning of this claim for the merchant info and for an investigator to contact me. They never have. I called again on XX/XX/XXXX asking for information and nothing. They refuse to issue any more credits and as far as they are concerned I am responsible for the fraudulent charges. These charges should have never been allowed in the first place because it put me over my credit limit. But they said because I paid my bills on time they allowed it, but my debit card was denied as it should have been. I did not make these charges and I dont know who did. I can only think of a few scenarios when I did not have my cards or I had to also try my Debit card. My belongings were on the boat when I was scuba diving. At the airport when I first learned of this. Or I was tricked by a women I went on a date with on XX/XX/XXXX, I remembered that she left for a while after I gave the waiter my card he came back and said it didnt work so I gave him my debit card, but my card was charged {$36.00} for the dinner. I XXXX, I only know that women I met in XXXX. I wanted to take meet her in XXXX in XX/XX/XXXX, but her brother whom I never met, would not let her go. We exchanged passport and driver license info in XXXX to convince him she would be safe, but he said no. I recently accused her of using my cards but she denied it. I don't believe she did it, but because I accused her, I may have lost a good friend if she was innocent. I just don't know how else she would have had the opportunity to access my cards, we spent so little time together. I know she is a dental assistant but I wonder if the waiter was real or someone she knew. Bottom line is I did not make the purchases nor did I authorize anyone to do so. I got the card to save on foreign transaction fees but after this happened I thought I was protected from fraud too. The contract says I am protected but they claim I made the purchase, I did not.