Product: Credit card or prepaid card

Date : XX/XX/XXXX, Amt : {$1500.00}, Citibank failed to perform its due diligence to investigate the my complaint with current information. The decline made by Citibank on XX/XX/XXXX failed to show that they performed a substantial investigation and their conclusion was based on stale and inaccurate information from the merchant in XX/XX/XXXX. Citibank stated that the information I provided was not substantial documents. I provided the actual screen shots of the online chat with the airline representative to show that the tickets were not valid. I also documented the conversation I had with the airline representatives that the tickets were canceled by the merchant. If Citibank had truly performed the investigation, they would have found out that the merchant had gotten my refund from the airline since XX/XX/XXXX and that the airline would not provide substantial documents to the customers since the reservation was made via a travel agent. 

On XX/XX/2020XXXX, I spoke with XXXX XXXX representative, XXXX , regarding XXXX order, the representative confirmed that the refund was provided to the XXXX parent company, XXXX XXXX XXXX , on XX/XX/XXXX. This was the date that Citibank closed the case and debited my account. I emailed my refund requests to XXXX customer service numerous times, there was no response. On XX/XX/XXXX, the Communications Director, XXXX XXXX from XXXX responded to my email after I sent the request to the merchants CEO. Mr. XXXX denied of receiving the refund from the airline and provided inaccurate information stating that XXXX airline had told them that they were not able to apply a full refund and I have to proof that the airline would promise a full refund. On XX/XX/XXXX, I received an email from the airline verifying that the refund for my reservation has provided to the travel agent. I provided the email proof to the travel agents CEO and Mr. XXXX, there was no response. The travel agent did not deliver the service to me on XX/XX/XXXX and took my money. 
I did make a flight reservation with the merchant, XXXX XXXX and I did receive the confirmation 8 days after placing the order. However, the service was supposed to deliver on XX/XX/XXXX did not deliver by the merchant. My departure date for this reservation was XX/XX/XXXX. The merchant unilaterally canceled my flight reservation on XX/XX/XXXX, some hour before my departure date. I provided the screen shots of the airline chat records to show that the tickets were not valid on my departure date, XX/XX/XXXX ( # 5 ). How did I get service from XXXX on XX/XX/XXXX when they purposely canceled my flight tickets on XX/XX/XXXX? I performed the agents job to gather evidence from the airline to proof that both Citibank and the travel agent did not perform its due diligence. 
I understand Citibank wants to make fees out of this transaction by ignoring consumers rights. Based on Citibanks imprudent and irresponsible conclusion, I do not feel that I am protected under the Fair Credit Billing Act from unfair credit billing practices. I was charged for " goods or services not received. While the airline has provided my refund to the travel agent, they failed to properly reflect payments or credits to my account, instead they stated that the airline did not told them to refund me ; and the merchant failed to provide written proof from the airline that a refund for the inquired reservation is not possible. With all the proof, Citibank still think the merchant entitles to the payment even though they did not provide me service. Citibank should provide training to its staff on how to investigate and analyze the dispute. 
Further, Citibank never accepted my complaint as a billing error. There was no record showing that such dispute was entered into my account. However, my clean account was reported to the credit agencies as past due. It was not my misunderstanding of Citibanks negligence. Citibank failed to investigate my account by imprudently put in a robotic and standard language to defame my good standing account. 

I dont know what kind of document is considered substantial to Citibank? All I know is that Citibank did not do its job. If Citibank wants to verify whether the facts provide by the customer are substantial, they should contact to the airline to verify the information instead of relying solely on the merchants outdated and invalid information. The merchant still show that the tickets are open in their internal system ( # 6 ). This is the merchants system, they can leave the ticket status :  open, canceled or closed. The airlines system has the final say. The airline is the one to collect the money and provide the refund. The tickets were booked via the travel agent ; hence, only the travel agent can request document from the airline. Citibank is well aware of the US travel agent rules, but they refuse to recognize the merchants fault or perform an investigation by victimized its customer.