Product: Credit card or prepaid card

History as of XX/XX/XXXX Closed account with Citibank Mastercard XX/XX/XXXX ; due to COVID, I was not traveling anymore and did not need this credit card. 
Last authorized use of credit card was XX/XX/XXXX at the XXXX XXXX for {$27.00}. 
I made my last payment to clear my balance of {$27.00} on XX/XX/XXXX. 
Citibank allowed an unauthorized charge in XXXX, XXXX from XXXX XXXX ; I have told Citibank that I did not authorize this and I did not purchase anything from XXXX in XX/XX/XXXX. 
Received call from collection agent in XX/XX/XXXX ; up to that point, I did not know there was a balance on the account because I had closed it. 
Called Citibank XX/XX/XXXX and talked with multiple people who admitted that my account made no sense. Citibank said they would order an audit to investigate what happened and I should hear from them in 2-3 weeks. 
I never received contact from Citibank except for calls/emails to pay the balance. 
I called back XX/XX/XXXX and spoke with XXXX, XXXX, XXXX and finally XXXX, an Account Manager. XXXX looked at the account and said your account does not sense. This is not your fault, I dont know why the audit has not been completed. She said she would look into why the audit was taking so long and call me. I never received a call back. 
The ball is in Citibanks court to clear up this unauthorized charge. They have verbally admitted this to me multiple times. However, my credit is being impacted and that is not ok. I have done nothing wrong and have no confidence that Citibank will take any action to resolve this. 
I plan to file a complaint with the Consumer Financial Protection Bureau. 
Who is going to fix my credit rating given this is clearly not my fault and I have gone to great lengths to try and get resolution with Citibank???? 

XX/XX/XXXX : XXXX XXXX Called Citibank Disputes, XXXX Got to XXXX, # XXXX, she informed me that no one at Citibank can see my account ( no log, no audit, nothing ) due to it being sent to Recovery ; she said I had to call Recovery, they were the only people that could see my account ( XXXX, XXXX XXXX XXXX XXXX XXXX M-F ) XX/XX/XXXX : XXXXXXXX XXXX called Citibank Recovery, XXXX got to employee # XXXX, he told me because it was a NC account, he was not authorized to work on it and had to transfer me was transferred, XXXX, # XXXX call XXXX, ask for Dispute on charge acct in XXXX when account was closed called Disputes, instead got XXXX, # XXXX, Client Focused Team ( XX/XX/XXXX, {$8800.00} ) XXXX gave me wrong number, XXXX now going to transfer me to Dispute # XXXX XXXX, # XXXX, gave her date and amount of charge, needs to transfer again XXXX, identifier XXXX ; after holding, she came back and said she had to speak to her investigation department about the audit that was performed ; she read audit results to me, which included a letter and reference to statements, which I never received. 
XXXX transferred me to Dispute department, XXXX # BDXXXX ; asked if I received a letter dated XX/XX/XXXX via email, I told him no. He said he is going to email it to me. If I dont get email in 24 hours, call XXXX ( Billing Disputes ). 
Review email, contact XXXX XXXX investigator for next steps or questions XX/XX/XXXX : XXXXXXXX XXXX received secure email, downloaded. Letter referenced a letter on XX/XX/XXXX that I did not receive and also statement copies which I did not receive. Per the instructions I was given on XX/XX/XXXX, I called XXXX XXXX at XXXX ; there was a voicemail that said that phone number was not being checked and people should call Billing Disputes at XXXX Called Billing Disputes, got XXXX, then call dropped off Called BD again, got transferred to wrong place and call ended Called BD again, got transferred twice, got to XXXX, # XXXX, she transferred me XXXX, # XXXX, transferred me XXXX, Customer Service, call dropped Sent email to Billing Disputes requesting information ( email attached )