Engine repair service near Alcoa, TN

Halls Service Center has lost my business. I went to Halls Service Center and asked them to check only the code from the car's computer, a job that takes literally less than ten seconds. Places like Firestone do it for free. But when I came to pick up my car, they wanted to charge me ninety dollars because they had done a full diagnostic scan on the engine including a test drive. When I explained that I had asked for only a code check, I was told that they don't do just a code check, only a full diagnosis. If that's true, then they should have told me at the beginning instead of charging me for a service that I did not request. I tried to get things worked out with a manager, but before even listening he told me that he wouldn't consider waiving the fee because he was already convinced that his garage was in the right. The man at the counter claimed that I never said that I only wanted the codes checked, and the manager said that the mistake was 100% my fault because I hadn't double checked about what was written on the order or asked about the price. He was right--it certainly was my mistake to trust Halls Service Center to perform only the services that I asked for and to trust that they would charge me a fair price for it. My conversation with the manager was calm and outwardly polite, but he ended up implying that I was just too cheap to take care of my car the way I ought, and the guy at the counter made it clear that he thought that I was lying and trying to cheat them. Eventually, the manager threatened to lock up my vehicle and start charging a $25 a day storage fee if I didn't pay up, which I eventually was forced to do. Even though I have used Halls Service Center several times before, I'm not going to take my business to a place that doesn't have a problem with a customer leaving feeling like he's had money twisted out of his hand.