Complaint sub-issue: Credit card company isn't resolving a dispute about a purchase on your statement

I have been with Citicards for over 19 years, and in XXXX, I had a recent experience with over {$13000.00} of fraudulent activity, where at Citibank and CitiCards handled it extremely poorly. They ended up giving me a credit for the investigation, but not right away, and they would not allow me to use my card, so I applied for a different credit card with a different bank which I got approved for and canceled my city card because I needed to use a credit card right away. I had a bill from Citicards that was due in on XX/XX/XXXX, which would have been my last bill with them. I called up because some of the charges on that bill on that statement were some of the fraud charges, and I just wanted to be sure that I got a credit for all those charges and that I was not paying for any of those fraud charges. The representative told me to pay for only the amount that I charged ( {$1700.00} ), and not any of the fraudulent charges. I added it up about three times, just to make sure everything was accurate and I paid that amount. I also confirmed with her that I would not receive any interest charges because I was not paying for any of the fraud charges on my account, and she said that I will not receive any interest charges. I Paid the bill and thought everything was all set. A week later, I get a another bill from CitiCards, but the representative told me I would not be receiving another bill from them because I did not use the card since the middle of XXXX. The bill was for over {$500.00}, plus I got charged interest on that bill, which the representative told me I would not get charged interest on. I called again and I was on the line for over an hour and a half, speaking to different people. I spoke to manager, XXXX in Arizona, and he was back-and-forth with the security department, but they could not figure out what was going on and he said he would call me back. He never called me back that day, but I did receive a voicemail from him on the next day. I tried calling him back, but he was not available, so I left a message for him to call me back and he never did. It is now two weeks later and this mystery bill that I received is due in a week, that I do not owe any money on. I tried calling this morning to speak with somebody to rectify this so they can figure it out on their own time and give me a call back, but I was hung up on five times this morning. I was given miss information between departments who I needed to speak to. I was transferred seven times between different people. I asked to speak with a manager who can rectify the situation, but I was transferred between customer service, between security operations, between fraud department, and nobody seems to be able to help. After the seventh time that I was transferred, I hung up the phone and just said I was going to file a complaint because nobody over there seems to be able to figure out the situation or knows how to help me. This mystery bill is due in a week, and Citibank will destroy my credit if this is not resolved. Its not fair, considering this is something that I do not owe, so I would like at a higher up manager to contact me to figure this situation out, so I am not given the runaround and being transferred amongst all these different departments who can not help me.