Product: Debt collection

I had a debt of {$2800.00} with Toyota Motor Corp after my lease was turned in. The debt was sent to a XXXX XXXX XXXX ( collection company ). In XXXX of XXXX I agreed to a payment plan with this company to withdraw {$100.00} monthly from a bank account that I set up strictly for this debt. In XXXX of XXXX the debt was paid as money was no longer debited from my account. In XX/XX/XXXX I closed the account. I worked the math and the debt was paid off in the amount of {$2900.00} ( XXXX too much ). In XXXX of XXXX I receive a letter from another collection company, XXXX  claiming I owe an additional {$100.00}. I immediately called them and placed the account in dispute telling them that I have proof the account was paid in full. On XX/XX/XXXX I called them back to see if it had been resolved and I was told that the account could not be accessed because it was placed in dispute and that I should wait a little longer. On XX/XX/XXXX, I also tried to contact Toyota Financial,  but they could not talk to me about it because it was in collections and I had to deal directly with XXXX On XX/XX/XXXX I emailed a letter to XXXX stating my case and asked them if I can send them all the proof I had that debt was paid. Later in XXXX I receive a letter from XXXX ( letter is not dated but I have the envelope that is dated XX/XX/XXXX ) that includes my payment history with Toyota and  XXXX combined. The payments listed to XXXX were not correct and didnt make much sense ( wrong dates and amounts ). I've called XXXX several times ( all have been documented ) and nobody can help me because the account is in dispute and I just need to wait until someone contacts me. My last call to XXXX was on XX/XX/XXXX with the same answer. On XX/XX/XXXX I receive a call from XXXX from a girl trying to collect the debt. I told the girl that I needed answers as I did not owe this. XXXX claims that she looked into it and it was in fact in dispute and she couldn't help me. On XX/XX/XXXX I received a call from XXXX, yet another collection company trying to collect this debt. Once again, I explain my situation. The guy said he couldn't see anything on my account, but he would look into it and get back to me. I left him my cell number as well as my work number that he called me on. He left me a message on XX/XX/XXXX that he had answers for my on my debt. ( I was on vacation had had terrible service so I didn't call back immediately ). I  called back on XX/XX/XXXX and talked to the same guy. He now tells me that an additional {$120.00} charge was assessed on my account from Toyota for in XXXX of XXXX for personal property tax on the car. WHAT? I told him that this couldn't be and that this is a mistake. He demeaned me because " I didn't understand the personal property tax rules in my state ''. WHAT? He tried to strong arm me to pay the small amount and get done with it. I told him I was checking into it which he snickered about. I DO NOT OWE this money. I have every bank statement showing all my payments. I have every single date and time and notes of my calls. I have a copy off my email. I have everything I need to prove that this debt has been paid in full. I feel at this point that I have done everything right and paid my debt and try to square away any issues that came up after it was paid off. I have been disregarded by each company and at this point I am being harassed. Every call should have been recorded from these companies as they stated that disclaimer at every call. If this has is a scam and my information has been stolen from Toyota this opens up another issue. I am furious! 
As a side note : I have every bank statement showing XXXX XXXX debits but will not attach them in this email. If needed for further use, I will provide