Goodwill Transmission A promise to fix my transmission but instead destroyed after collecting thousands of dollars from me Plesantville , New Jersey

I had a problem with my transmission, took the car to a mechanic I was referred to. my warranty will cover to get another new transmission but he insisted that they rebuild transmission and I should go with that. I let them rebuild it and he gave me a 12,000 one year warranty. I used the car for about a month and parked the car for few months I barely drive it. so when I started driving the car again, I had a problem with the transmission again. it was less than a 3 months and I barely had about 7,000 miles. So I took the car to him but he gave me a bogus excuse that the warranty can't be use because of some issue which is not valid. He told me the company ownership changed but i was told its a family company. He fixed the car and I had to pay for it and in less than six weeks the transmission had a problem again I took it to him and  he said its one default with one thing and he showed and then fixed it. when I got it back he fixed and less than a week I had a problem with the transmission again. and I took it to him and he said that I have to pay again for him to fix. He has been been takin advantage of me and when I take the car to him he takes about a week or two to open and see what the problem and then take another two weeks or more before he fixes it. So since I started driving the car, I took the car to him, I use the car for about two months then take it down to him and then to him spend another months in his shop. I spent thousands of dollars only for him to to tell me a year later that my transmission is blown.