Product: Credit card or prepaid card

I am writing to complain about CITI Bank for - Placing an inaccurate charge which generates a wrong balance on one credit card that's already closed. Furthermore, CITI BANK flagged this account as 30 days past due because of this mistaken balance. This flag significantly harms my credit history and brings my credit score 61 points down immediately ( XXXX - XXXX, please see the attached screenshot ). In my XXXX credit history, this is the first and only time I have received a credit flag. Because of the mistake from CITI BANK, my financial plan ( refinancing and mortgage ) is significantly messed up. 
- No actions as promised up to 7 business days after two phone calls with their customer service department. Both representatives in the phone calls have confirmed it's CITI BANK 's mistake and promised that CITI BANK will fix it soon and send me written mails for further information. 

Context and Timeline : XXXX : - I noticed from the Citi mobile app that my prestige card account had been closed ( last 4-digit XXXX ) without receiving any notification. 
- I immediately called CITI Bank Customer Service ( on XXXX ) and told the agent that I had not received any notification about the decision. The agent told me that they had mailed me a letter and that no email had been or would be sent. I had not yet received the letter by that time. 
- During the phone call, I tried to understand if there was any way to reactivate the card. I was told that once the card had been closed, it could not be reopened. I was very disappointed and decided to cancel all my CITI credit cards ( including another Citi reward car d ) and pay off the balance. 
- Over the phone, I double-checked and was given confirmation by the agent that my total balance due was {$2000.00} and that the {$490.00} membership fee included in the final balance charged for XX/XX/XXXX- XX/XX/XXXX would be reimbursed ( because the card was canceled in XXXX XXXX, so no service was rendered ). The payment was made over the phone on XXXX and was processed successfully ( Please find the attached email confirmation ). 

XXXX : - I received one notification from XXXX indicating that CITICARDS CBNA has flagged my account as 30 Days Past Due on XX/XX/XXXX. This is marked as XXXX XXXX XXXX ( 30 Days Delinquent ), and my credit score had dropped 61 points because of this. 
- I immediately checked my CITI BANK accounts, and it turned out that the {$490.00} membership fee was not reimbursed despite the cancellation of the credit card INITIATED by CITI. This is different from the confirmation I received from CITI BANK Customer Service during the XXXX phone call ( In the later phone calls, I asked CITI BANK agents to check the recording of XXXX phone call but got rejected ). 
- I contacted CITI Bank Customer Service Department. One of the supervisors checked my case and acknowledged that it could be CITI BANK 's mistake. But she told me that they could not offset the balance for me ( because " XXXX is such a large number ) and that I needed to write a paper letter to Citi Bank by myself to ask for it. 
- I asked the agent if I could get anything written for this case and detailed instruction for this letter ( including the address and required material ). The agent promised that they would send me an email after they found the suitable template within 1 - 2 business days. 

XXXX : - Two days after the XXXX phone call, I had not yet received any email but a voice mail asking me to call back CITI BANK Customer Service XXXX I spoke with a different agent and had to re-explain my case again to convince her to check the notes left by previous agents. She said in the notes the mistaken balance was acknowledged, and they will clear my balance. I asked about the effect on my credit history and the written promise by the previous agent ; she said that because they CAN NOT SEND AN EMAIL, I would receive a paper mail with instructions for me to write back to CITI again asking to dispute the credit effect. 

XXXX : - I have checked my CITI BANK accounts- and I still see the past-due balance. No mail nor email has been sent to me about this case, and no further communication from CITI BANK on this matter. 
- I spoke with an agent and her supervisor for two hours and the supervisor promised me that she was resolving all my issues step by step over the phone and I dont need to call back again, including : 1 ) clear my account balance to 0 2 ) write to CITI credit department to withdraw my collection from the credit bureau XXXX She gave me a confirmation number as XXXX. And promised me that the balance will be cleared by XX/XX/XXXX, the collection will be withdrawn be XX/XX/XXXX. 


XXXX : - Neither is resolved as promised. The CITI BANK didnt clear my balance but even used my checking account for the payment. And the most ridiculous thing is every time the representative told me that they have put notes but every time I called, no notes can be found on my account that I have to spend hours explaining my case and deal with the questions. 

Throughout the entire process, what I request from CITI BANK is simple ( and they have already promised me both ), yet NEITHER is delivered : clear the balance on credit card XXXX. 
remove the collection flag on my credit report.