Product: Credit card or prepaid card

I am writing to you to voice a concern and an issue I had with my Citi XXXX XXXX with you ending in XXXX. So to explain the situation that arose was that I had issued a balance transfer from a card at another institution. That was completed on XX/XX/XXXX and I was charged a {$290.00} for my balance transfer. Which was agreed to along with the 0 % balance transfer rate though XX/XX/XXXX. Which I was perfectly fine with and what I wanted. So the next month I thought I changed my AutoPay to pay the minimum balance and not the statement balancewhich I thought I changed. I guess I didnt and had a charge of {$10000.00} come out of my checking account on XX/XX/XXXX and overdrew me. So when I saw that I called CitiCards to get this resolved. The person I spoke to on the phone said to just update the AutoPay and I wouldnt get charged again and it would pull my minimum payment. So I changed and updated it all I thought was good. Then again on XX/XX/XXXX CitiCards charged me for my statement balance again in the amount of {$10000.00}. Which again overdrew me with my checking account. I called CitiCards again to try and resolve this and they told me that I would need to place a stop payment at my bankwhich is not what the Rep stated the previous day I called. So I proceeded to place a stop payment at my bank to stop this charge. I then went and made an additional payment to my Citi Card for {$200.00} to make sure I wasnt late on my payment. My account was setup for AutoPay for the minimum balance after this whole fiasco. So my autopay was setup and everything was good so I never looked back since there were no issues. Now when I am doing my taxes and reviewing documents I noticed that my Balance Transfer Promo is no more.its gone! After doing some research I noticed that my balance transfer promo that was agreed to on XX/XX/XXXX for 0 % till XX/XX/XXXX was removed because of this whole autopay debacle. So I paid a balance transfer fee for 0 % till XX/XX/XXXX and only granted me the balance transfer fee for one month because of the payment mishap. I think this is not right and someone should look into why this happened and ethically it is not fair I lost my balance transfer rate. So from the CitiCard rep that I spoke to place a stop payment I think they should have informed me that I lost my balance transfer promo that I paid {$290.00} back in XX/XX/XXXX. Citi should look at resolving this and I have been a customer of yours since XXXX! So I called last night on XX/XX/XXXX and spoke to a rep who transferred me to their supervisor who was unwilling to help and was quite rude with her responses and refusal to even have someone investigate this. As to why it happened and why no one at Citi Cards caught this mistake as to my promo rate being removed for an error in an auto pay payment. The supervisor refused to help me and kept saying there isnt an option for my requestthere is no option. Isnt there an option to send an e-mail to their boss or supervisor to look into this matter that caused me to incur over a thousand dollars in lost money? NO she refused and said there is nothing she can do. I stated there are regulations and rules against things like this and she needs to get her supervisor on the phone or make them aware of this situation. She again refused and said there wasnt an option. I couldnt spell her name but got her employee id which was XXXX I think. It is just concerning that I have been a valued customer and paid a lot of money in interest for close to 17 years with you and the supervisor was unwilling to help and continued to state there isnt an option. So after looking at statements this would mean that Citi Cards has mis-appropriated my payments in the amount of {$1000.00} roughly give or take the statement cutoff date.that I was getting charged in interest that I wasnt supposed to and was supposed to be going to my principal. In addition to that I paid a balance transfer fee and made an agreement with Citi Cards that I would be guaranteed the promotional balance until XX/XX/XXXX for a fee of {$290.00} which I paid that fee. I would like someone to look into this and get this corrected for me since I wasnt at fault and it was a system glitch or error that occurred to remove my promotional balance back in XX/XX/XXXX and had the returned payment account for a purchase interest rate. I tried calling multiple times to rectify this and thought it was correct and shouldnt be penalized for this occurrence. In addition I was trying to speak to an agent last night XX/XX/XXXX via chat after the supervisor refused to help me. It was funny I got connected to the chat then said I had to wait. I got a notification that the rep was available and typed my questions to them. Got no response then I got a response and I was trying to get into the chat and the XXXX magically froze and shut down. This happened nearly 10 to 15 times so I could read what the rep said or reply. The app worked fine viewing my balances and statements about once I went to the chat the app shutdown. Very frustrating and think this was done on purpose since the supervisor who I spoke to earlier was still working and may have had a hand in shutting down my chat on their end. Someone needs to look into this and get back to me.