JT Diesel Performance

I came to JT Diesel Performance for a free diagnostic for my Truck that lost its reverse gear. John T the owner performed a diagnostic for free to check to see the issue/cause of the problem. He said it was our reverse band on our Transmission and we would need to have our transmission replaced. We gave him our budget of around $300-600 to do a Transmission Swap to get our Reverse Gear back once we acquired a new transmission. We paid $500 cash down to put towards any work while we hand the funds available. We acquired a new transmission and took our truck and new part to JT Diesel Performance's shop. John T said he had another project being done but would get to us right away. JT Diesel never provided us a Estimate of the work that would be done before work was performed. John T did not have the equipment or knowledge to perform the task of and had to have our Transmission taken to a 3rd Party Transmission Shop. JT Diesel Performance had our truck for 3 weeks. Finally they said our truck would be ready on a Wednesday. My boyfriend went to pick up the truck. They charged him another charge of nearly $500. AFter payment John T said the truck still did not go into Reverse, that the issue was not fixed. We took our truck to another Mechanic shop, got and estimate of the repairs that needed to be done and put it into that shop. I called JT Diesel to ask them why they charged us so much money to fix my reverse gear when they didn't fix anything. They wanted to have a meeting in person because they felt they didn't owe us anything back that they did not overcharge us. I went the following week to meet with John T and his associate Cody K to discuss the amount I felt was over charged and wanted a partial refund back or I was willing to go to small claims. When I was talking with John T he would begin to yell and raise his voice at me. I ask him multiple times to lower his voice please and to not yell at me, then he began to curse at me, call me names, and I left.