Product: Credit card or prepaid card

Dear CFPB, I received a charge from XXXX on my credit card statement for {$8100.00} which I did not make. The charge was posted on XX/XX/23 and I created a billing dispute with Citibank for the charge. They placed a conditional credit on my balance and asked for more information. 
XX/XX/23 - Called XXXX to understand this charge and they informed me that this charge did not exist in their system and it was fraud and to address it with my credit card company. 
XX/XX/23 - Sent invoices and a letter describing how this charge was not made by myself or XXXX. 
XX/XX/23 - Received a letter from Citibank saying that they did not receive documents so they closed the dispute and reversed the credit. 
XX/XX/23 - Called Citibank. They saw that the documents were received and told me that the dispute would be reopened and the credit would be reapplied. 
XX/XX/23 - Put in a dispute with XXXX and quickly received a note saying that this is fraud, the charge does not exist on their system and to take it up with my credit card company. They provided the dispute number and resolution. 
XX/XX/23 - Since Citibank didn't reverse the charge I called again to find out that the case was not reopened and no action was taken. Spoke to XXXX XXXX who said she would get the case reopened and I would see the credit in 5 days. 
XX/XX/23 - Called Citibank again to see why this is being treated as a billing dispute and not fraud as the vendor is saying it's fraud. XXXX at Citibank said they had to treat it as a billing dispute as XXXX has my credit card number so I am thier customer. They said they can't treat it as fraud even though the vendor is saying they did not make the charge. Was told that the case would be reopened and it would take 5-7 days. 
XX/XX/23 - Called Citibank as no action was taken on my account. Spoke to XXXX. I was told that my case was not re-opened but he assured me that he would get it opened, I would see a response from Citibank in a week and the charge would be reversed in 5-7 days. He asked for the response from XXXX with the case # and resolution, which I sent through email that day. He assured me that this would be resolved in a week due to the large amount. 
XX/XX/23 - Called Citibank disputes again as no action was taken on my account. Spoke to XXXX. She confirmed that my case remained closed and no action has been taken to resolve this. She saw all the prior work orders, all the documents I sent in, including the one from XXXX saying it was fraud and all the notes from the prior calls. She said that she woudl put in a work order to have it re-opened. I let her know that I have been told this multiple times and there has not been any action and I would like this escalated. She let me know there is no escalation path and there was no XXXX XXXX to have this resolved. I asked if a XXXX has other options and was told no and to call back in a week if there was no action. 

As you can see, I have taken action many times to have this fraudulent charge reversed and Citibank is not taking action. They actively gave me incorrect information many times and all the commitments they have made to resolve this have not been acted upon. I am looking to have this charge reversed from my account as it is invalid and fraudulent. Even the vendor is calling this fraud so I can't see why this is lingering. 

Please let me know what other actions I can take to get this resolved as soon as possible. I appriciate having an government organization I can turn to which fights with me on these issues. 

Thanks, XXXX XXXX