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

I did not receive everything I paid for so I created a dispute with Citi Cards over the phone on XX/XX/XXXX at XXXX XXXX. for a {$1000.00} charge on XX/XX/XXXX. When I created the dispute they asked for the transaction amount and the date, but when I started to tell them about the specifics they told me " they would contact me if they needed anything else ''. I made multiple calls over the next few months only to be told they were waiting for the merchant to respond. The next correspondence I received on XX/XX/XXXX dated XX/XX/XXXX from Citi was a letter that said " we determined that the service for which you were billed was provided ''. This dispute was not over a service provided it was a car, key and switches that was to be installed with it. From the beginning their dispute department did not investigate this claim properly or receive any additional information I had to support the claim. I immediately called them on the XXXX after receiving the letter to explain why this dispute was not completed correctly. They stated they had sent a letter that would need to be signed to continue the dispute but I had not received it. They also said it was on the website but the agent could not find it on there either. Then she said she would resend the letter that I would need to sign along with my supporting documentation to continue the dispute process. I asked if she could email or fax that and the response was no they needed the hard copy. At that time I emailed all of my supporting documents so she would have it. I then received a letter on XX/XX/XXXX dated XX/XX/XXXX that was mailed with a form to sign stating it needed to be faxed back by XX/XX/XXXX. I called again that day since the time frame had passed before receiving the letter and was told to sign the form, return it with my supporting documents and that they would reopen the dispute. I sent 12 documents showing that the purchase was supposed to have the convertible top actuator switch, reverse button, and window switch fixed. None of those items were fixed and I have documentation where I had them replaced for {$820.00}. The vehicle was supposed to be shipped with a new key also since the old one did not work, and that was not sent either. The key cost {$290.00} plus {$300.00} for shipping the car to the closest dealer in XXXX OH ( total {$1400.00} ). All of these items I have documentation from the owner stating he would fix or send with the car, but was not fixed or sent. This cost me {$1400.00} over the {$1000.00} I had disputed on my credit card. I also have documentation where I asked if the after market wheels rubbed which the owner said no. I have included documents the show this to be untrue, but still do not have a total cost to fix this issue. The next correspondence I received was a letter from Citi dated XX/XX/XXXX that came in the mail XX/XX/XXXX. This letter stated " As previously stated we are unable to require the merchant to issue a credit for this charge since the time frame in which to resolve a dispute has passed ''. Because of their lack of communication and poor dispute process the time frame where XXXX would have corrected the issue had expired as well. I have all of this information documented through email and time stamps on my phone. 
Since then on my next statement I have paid the balance on my Citi account off ( as I do every month ) except for the {$1000.00} disputed charge and closed the account. I have also sent Citi a certified letter on XX/XX/XXXX stating the issues that I had and not to continue to pursue collections for the disputed {$1000.00}. This obviously did nothing as they have turned the account over to XXXX XXXX XXXX a debt collection agency, and this is why I am seek other recourse 's now. If you would like a copy of anything that I have stated not included please let me know. In 20 +  years I have not had a late or past due loan or credit card payment, and this is the first issue which is affecting my credit score also. All said Citi delayed and gave me the run around until their dispute time frame had expired. Thank you in advance for helping to resolve this Citi Card issue. 
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