Product: Credit card or prepaid card

On XX/XX/XXXX, I noticed two unauthorized ( {$22.00} and {$85.00} ) activities with my Citi/ Costco Anywhere Visa Card . I called Citi Bank to report fraudulent charges. My card ended with XXXX was closed and Citi issued me a replacement card, which was out for delivery on XX/XX/XXXX. 
On the night of XX/XX/XXXX, I noticed another unauthorized charge ( {$280.00} ) made with the replacement card which I HADN'T RECEIVED yet. I called Citi Bank again to report this fraudulent charge when it was still pending, but Citi 's customer service agent told me to WAIT until the charge went through to file a dispute. ( They could have canceled the transaction and stopped the payment AT THAT TIME!!! ). I didn't activate my replacement credit card until XX/XX/XXXX and avoided using it for fear of further fraudulent activities with this card. 
Ever since then, I have received numerous email messages from Citi Bank, asking me to reply with required information to help with the investigation, which I did. 

On XX/XX/XXXX, I paid off all the balance on the Citi/ Costco credit card ending in XXXX and cancelled the card because I have been so tired of the hassles of inefficient investigation,. 

On XXXX XXXX, I received a message from Citi Bank, telling me that their Billing Department completed the investigation and transfer my case to their Security Investigation Department. They also decided that it is MY RESPONSIBILITY to pay {$280.00}, so they charged it to my credit card ending with XXXX ( THIS IS a FRAUDULENT charge! ). 
On XXXX XXXX, I called both Citi 's Billing Department and Security Department and talked to them for hours. The security department said they couldn't access my case since it was just transferred to their department and the Billing department told me that I don't have to worry about the payment until XXXX. However, I will have to pay the LATE FEE if I don't pay the {$280.00} charged by Citi Bank. 
On XXXX XXXX, I logged into my Citi Bank account and noticed that I was issued another replacement Citi/ Costco Visa card, which I DIDN'T REQUEST AND DIDN'T WANT. I called Citi 's Customer Service to cancel the card and asked them to put the unauthorized charge of {$280.00} under the " fraudulent dispute '' instead of " purchase dispute ''. Unfortunately, the customer service agent DIDN'T INFORM me that cancelling the unwanted/ unrequested Citi/ Costco credit card would make my Costco membership number INVALID and I wouldn't be able to access my Citi online account any more! 
On XX/XX/XXXX, I replied a call from Citi Security Investigation Department and had to provide the same information that I had done every time I called Citi Bank. The agent from Security Department told that I will have to call back to get updated information regarding their investigation. They WON'T REACH OUT to me for any updates!!! I also noticed that I was not able to log into my Citi Bank account on XXXX XXXX. 
On XX/XX/XXXX, I realized that my Costco membership number was invalid because I called Citi Bank on XX/XX/XXXX and asked them to move my case under " fraudulent dispute ''. 
On XXXX XXXX, I called Citi 's Customer Service and asked them about how they had the right to make any changes of my Costco membership number after I closed and cancelled the Citi/ Costco credit card . They said it was Costco 's responsibility. I asked how I will be notified of any message about the investigation and the agent said I will get it from mail ( This is different from what I was told on XX/XX/XXXX! ). 
I am really tired of and frustrated about my experience with Citi Bank regarding how they handled the fraudulent reports.