Product: Vehicle loan or lease

On XX/XX/2023, I purchased a used car from XXXX XXXX XXXX XXXX in XXXX, NJ. 
As part of the purchase, I applied for and was approved for financing through Credit Acceptance. The car was advertised for sale at {$10000.00}, and despite the car having several CEL codes, I agreed to the price. During the signing of the loan agreement, the dealer stated they needed to add on {$860.00} of charges " in order to meet minimum loan balance requirement for loan eligibility ''. The charges were included on the sales agreement as " Accessories '' and consisted of itemized charges for floor mats, trailer hitch and wheel locks. None of these accessories were actually included with the car on purchase. 
A day after the purchase, the lender, Credit Acceptance called me to inquire about the Accessories listed on the purchase, wanting to confirm that those items were not fictitious. I informed them that the items were in fact fictitious, and were added by the dealer to meet the loan requirements for minimum balance. The lender apologized for the issue, and opened up an investigation on the dealer to get those funds refunded from my loan balance. 
On XX/XX/XXXX, XXXX and XXXX, the dealer contacted me by phone and then by text messages. They were somehow alerted of the complaint that was filed by the lender, and were extremely hostile and aggressive in their communication with me. They flat out demanded that I cancel the complaint with the lender, or else they would cancel the loan and repossess the car ( I have the phone screenshots showing these text messages ). I refused to cancel my complaint and demanded they stop contacting me because I had already bought the car and put a down payment on it, and had an active loan on the car with the lender. Several days later, I received an email notification from my lender, stating that my auto payments had been cancelled. A week later, the lender sent me a letter in the mail indicating they had " reassigned my loan back to the dealership, XXXX XXXX XXXX XXXX. '' Both the cancellation of my auto payments and the cancellation / reassignment of my loan from the lender back to the dealer were all done without my authorization. 
Right before I received the letter from the lender, the dealer again contacted me saying they had cancelled the loan, and demanded I return the car or else they would repossess it and would assess me more fees. I called the lender at the same time and demanded they undo the cancellation because I did not authorize it, and the lender refused to comply and stated that the dealer has the right to cancel loans in certain circumstances and refused to provide any further details A day later, I contacted an attorney, explained my situation, and the attorney sent a demand letter to the dealer demanding they stop contacting me, and cease any and all cancellations and unauthorized modifications to my loan contract, and also demanded a full refund of the {$860.00} of fictitious and fraudulent charges. My attorney also sent a demand letter to my lender, notifying the lender that they had violated privacy law by sharing personal information about the complaint with the dealer which resulted in the dealer taking retaliatory action against the customer. The letter also demanded that they undo the cancellation of my loan, reinstate my loan, remove any unauthorized parties other than myself from the loan contract, re-initiate any scheduled auto payments, and to not allow the dealer to make any further unauthorized changes to my loan agreement. 
I have not heard back from the lender, and it is now 1 month later. I want to keep the car, get my loan reinstated, and avoid any illegal repossession of my car. I need help getting this situation resolved as soon as possible and would like to avoid any costly legal fees that I would need to incur by taking either the dealer and/or the lender to court.