Product: Credit card or prepaid card

I booked a flight on XX/XX/XXXX by using Citi Bank Credit Card 's Thank You Point Reward program, with Trip ID XXXX, for flights on XX/XX/XXXX from XXXX XXXX to XXXX and XX/XX/XXXX from XXXX to XXXX XXXX. 

I cancelled the flight back ( from XXXX to XXXX XXXX XXXX on XX/XX/XXXX. I contacted Citi Bank by calling XXXX XXXX in XXXX to check my refund status. They told me they would send me a check with more than 300 dollars via mail ( because I downgraded my credit card in XXXX and they can not directly return the refund to my card ) and should arrive in several weeks. I called them several times by the time the check should arrive, and they said it might get delayed due to COVID-19, and it will take up to 8 weeks, then the ETA will be end of XXXX. 

On XX/XX/XXXX, I called them again since I haven't received the check, and they said the check has been mailed out in XXXX and I should have received it. I confirmed that I didn't so the representative confirmed my address with me to make sure they have the right address. She said she would file another request to Accounting Department to send me another check. On XX/XX/XXXX I called them to check the latest status, this time the representative told me there is no second check, because they are waiting for the Accounting Department to check whether the previous check has been cashed out before they can send another check. She said she would follow up with them and would give me a call back in 24-48 hours with the result. But no, there is never a call back from Citi Bank. So I called them again on XX/XX/XXXX to ask the result, the representative told me the Accounting Department hasn't got back yet, and there is nothing they can do but wait. She told me to check back in a week. I called again on XX/XX/XXXX, still no result. I called again this morning ( XX/XX/XXXX ), at first the representative told me they had sent out another check on XX/XX/XXXX, I said but when I called on XX/XX/XXXX and XX/XX/XXXX, I didn't get such response. Then she corrected that it was sent on XX/XX/XXXX, not XXXX. I asked her to double check because I was bluffed and not treated seriously before, then after 20min of waiting, she said the check was mailed in XXXX. I said I knew all the information and please get in touch with you accounting department to find out the latest status. Then I was put on hold and the line got disconnected when I was on the line for more than 1.5 hours and I never get a call back to give me the update.

It has been more than 7 month. Because of this refund issue, I have called them nearly 10 times. Every time I would spend 1-2 hours on the phone, waiting, repeating myself over and over for the same information to different representatives and always get the same result, which is no result. 

I respect the process and think it's necessary. But it shouldn't take this long and be this hard. The whole process is really frustrating because there is nothing I can do to speed this up or to escalate this when they can't get response from Accounting Department for more than 2 month. I was always told the same information but I can't see any progress. Please help me get my refund back.