Product: Credit card or prepaid card

On XX/XX/1019 I booked a cruise through XXXX. It was an XXXX XXXX XXXX cruise that included the cruise and the air fare. I used my XXXX XXXX  XXXX XXXX credit card and was paid for on XX/XX/2019. I was traveling with my sister-in-law and my niece. When my documents became available I went on line to change seats on the outgoing flight so I would have a seat near my sister-in-law and my niece. I picked a seat and paid for the seat on XXXX XXXX website. I paid {$65.00} on my Citibank AAdvantage credit card on XX/XX/2019 for the upgraded seat. At this time my sister-in-law had noticed that the date for departure of my flight was XX/XX/XXXX and it should have been XX/XX/XXXX. The cruise was departing from XXXX on XX/XX/XXXX and I would have missed that departure. My sister-in-law had set this trip up and then called XXXX, XXXX XXXX, to let her know about this error. XXXX advised that she would take care of this issue. I assumed XXXX contacted XXXX who then made the change in the booking for the flights with XXXX. XXXX only had record of my XXXX Rewards card number and had no information about the Citi/Advantage card number at all. On XX/XX/2019 I received confirmation of the correction of the flights for the correct day of departure. Also on XX/XX/2019 my Citi/AAdvantage card was charged an amount of {$1300.00} that I did not approve of or was ever made aware of until I noticed it on my account through my app. I immediately contacted Citi/AAdvantage card and told them that I did not make this charge and it was fraudulent. I set up a dispute with them and was told that everything will be ok and don't worry about it. Before I left on my trip I tried to track down what had happened and basically did all the leg work for Citibank. I mailed all the information I had to Citibank before I left on my trip. I also advised that that I will be leaving and would not be in contact with anyone until I returned. 
When I returned home I had the dispute paperwork sent to me in the mail. I then called them to tell them that I had already filled out this paperwork and mailed it into them. It took some time but they eventually found it. There was a lot of copies of conversations back and forth between XXXX via email and XXXX via emails. XXXX confirmed that they did not charge me and XXXX advised that my flight was booked through a third party ( XXXX ) not through me directly and they did not charge me either. On my credit card statement XXXX XXXX charge for the seat change was from XXXX XXXX. The other charge was from ( my ticket number ) XXXX XXXX California for the {$1300.00}. I questioned XXXX if they had an office in XXXX XXXX, CA and they advised me that they did not. I told Citibank dispute department many times and they said that had nothing to do with it. I have been asking Citibank to show me how the charges came into there location to see the differences between the two charges and I have yet to see any of this paperwork. XXXX has sent them all the information showing that I did take that flight that day and I am not saying I didn't. I agree that I have and that I paid for that ticket through XXXX. I provided the paperwork I received from XXXX of my final documents showing my ticket numbers and my seat change number. 
I have still been calling Citibank asking for document proof and they just keep telling me they are unable to get the merchant to issue credit for these charges. I keep telling them I would like to see how these charges came to them with no response to that request. I have told every person I have talked to at Citibank I have lost respect and confidence in their credit card because they are definitely not looking out for my interest. 
I would appreciate anything you could do for me at this time. I have been getting charged interest on this money now and have been paying a little off of it at a time. 
I am attaching the last big correspondence I have sent them that contains all the pertinent information. They also have the first big batch of emails correspondence I sent to them from XXXX and XXXX. 
Sincerely, XXXX XXXX