Product: Vehicle loan or lease

I leased a car from a XXXX XXXX through Chase Auto Financing in XX/XX/XXXX. It was 3 years long. In early XXXX of XXXX, I called Chase to ask for a lease to loan. They agreed and sent me paperwork to sign. I signed it and sent it back. I heard nothing back from them but they continued to accept my payments for the next 9 months, every month, without fail, so I assumed that everything was done and taken care of. That is, up until XXXX of XXXX, when my monthly payment to them was declined. I called to ask what was wrong. They said my lease matured in XXXX of XXXX. I asked how that was possible, I had a loan. They denied that I had a loan and that my lease had ended in XX/XX/XXXX and my account was charged off and reported to the credit agencies. I never once missed a payment from XXXX of XXXX to XX/XX/XXXX. They insist they sent me a letter in XX/XX/XXXX to tell me my lease was expired, but I never received any communication from them. I decided I no longer wished to do business with them and returned the car to the XXXX dealership XX/XX/XXXX. I have called Chase several times since then to obtain paperwork to prove that they mishandled my account and to ask for the status of the car return ( I no longer trusted them to contact me in a timely manner ). They promised me they would send it all to me by mail. I waited several weeks and called again, they said they SENT me the paperwork ( which I did not receive ) and that my car return was still " pending ''. On my last call to them several weeks ago I requested that they resend me the paperwork I originally requested and checked on the car return again. It was still pending. Last week I decided to begin a dispute with XXXX for the charge off, as I had no missed payments from XX/XX/XXXX to XX/XX/XXXX, which was when I returned the car. A charge off is usually for non-payment, but since I had proof that I was paying for the car and they were accepting payments for the car, then it should not remain a charge off on my record. Today, I received the result of my dispute. XXXX claims I missed payments in XXXX of XXXX and that I owe Chase {$3300.00} that I haven't paid ( I just saw this as of an hour ago and the banks are closed so I can't call Chase until tomorrow morning to resolve whether or not that amount is correct and what is the quickest way for me to pay them, AND why no one contacted me like was promised that my car return was done pending ). I have called Chase MULTIPLE time since XX/XX/XXXX to ensure that I did not owe them money and that they would tell me the moment my car return was processed so that if I DID owe them anything, I could pay them immediately. They never did so and now XXXX  claims I have not paid them anything for 3 months. Additionally, the paperwork I asked them to provide me with proof they mishandled my account was postmarked XX/XX/XXXX, but it claims that I had not yet returned the car ( which is a lie because I have proof from the XXXX dealership that I returned the car on XX/XX/XXXX XXXX. It also has copies of the letters they claimed to send me in XXXX and XXXX of last year, but there is no proof from the postoffice/official post mark to prove that the post office ever actually received or delivered these letters. I received this paperwork the week of XX/XX/XXXX, XXXX weeks from the date of the enclosed letter. My credit score has dropped over XXXX points because of this, which caused my long-term bank XXXX XXXX to reduce my line of credit, which increased my credit utilization, which further reduced my credit score. This is 100 % predatory by all banks involved and needs to be resolved by a 3rd party.