Product: Credit card

Our nightmare with the XXXX conversion from XXXX XXXX to Citi began in XXXX. We have an excellent credit rating and intend to keep it that way. In my XXXX statement ( originated from XXXX XXXX and transferred to Citi for payment ), I discovered a fraudulent charge of {$4100.00} against my son 's card from XXXX posted on XXXX XXXX, 2016 ( see attached ). My son did not authorize the charge. I did basic internet research and found the following ( screen shots attached ) : The type of business was identified as HealthcareHOSPITALS. 
A XXXX search turned up XXXX a cruise ship conference booking service for credit union professionals located XXXX XXXX XXXX MO XXXX XXXX XXXX 
A XXXX search turned up " No results found '' ( see attached ). This is a non-existent company. 
I followed the Citi " Dispute this charge '' online process, which failed : The site came back with " that content you are looking for can not be found. '' My second attempt yielded a case number ( XXXX ). Then I clicked " View Disputes '' and got the message " ... there are no dispute cases available for this card number. I called " Customer Service, '' ( XXXX ). I spoke with XXXX in XXXX XXXX/XXXX/2016 - Who said he did not have the authority to record a dispute of the charge without canceling XXXX Citi card. Since the Citi card was my son 's only access to funds while away in college, and the fact that the XXXX XXXX card the charge was made against was already cancelled because of the XXXX conversion, I asked to speak to a supervisor. 
Supervisor XXXX in Arizona who assured me that it went through and that it would take XXXX to five days to post : XXXX. She also said that late fees and interest have been suppressed pending posting and withdrawal of {$4100.00} charge. When I received my XXXX statement online it still showed the fraudulent charge with interest accrued with no recognition of the dispute. My account continues to show the unwarranted {$4100.00} fraudulent charge, including interest, now totaling {$5400.00}. 
Since XXXX I have spent countless hours on the phone with Citi " Customer Service, '' " Fraud Department '' and " Security '' in multiple conversations, being transferred to different people in different states, at different phone numbers, with different stories, with countless false promises stating that the disputed status will be reflected on my statement, and that the fraud department will resolve the issue and update my account to delete the obviously fraudulent charge from my account and my excellent credit rating not be affected by this erroneous charge. None of these Citi employees have followed through with the commitments they made. 

Instead, I and my family members have been receiving harassing, unfounded credit collection calls at all hours from the Citi Collections. When I described my experience I got apologetic responses and offers to be transferred to customer service. I finally demanded that any Citi contact only be made in writing. What I have received since is a " WE MAY HAVE A SOLUTION FOR YOU! '' letter from XXXX XXXX, Citi Vice President, advising that I set up a payment plan! 

Since XXXX I have been lied to and badgered by Citi representatives. It is evident that Citi refuses to recognize a disputed charge that occurred on the XXXX card number. I venture to guess I am not the only XXXX customer who had high-dollar fraudulent charges in their XXXX statement that transferred to Citi who have been stonewalled and badgered when attempting to clear the fraudulent charges. This leads me to believe that Citi has no intention of deleting the fraudulent charge and accumulated interest without my taking further action. Citi 's behavior is reprehensible.