ARS / Rescue Rooter Richmond

This company is CHEAT, I had issue with my new AC which was installed on July 2015 from the same company (this company is registered agent of Home Depot). I asked them to come and diagnose the issue. They charged $77. First, company send a junior technician, who couldn’t diagnose the issue. I Could not go to the other company as I already paid money. After 2 days, they send so called Senior technician and in 10 min he found there is a leakage in the coil. He did not check other parts. He told me that parts are under warranty but I would have to pay for the labor which is $ 1500. I agreed to pay and after one day, he replaced the coil. After changing the coils my AC was not working as expected, so I called them again. This time another guy came and he found issue with my Thermostat. He said the same thing, part is under warranty but I have to pay $240 for labor to replace my thermostat.
My questions to them was when I paid for diagnose charges, why you people did not check everything at that time. I am trying and fighting with the company to replace the thermostat without the charges… or give me the new thermostat I will replace by myself or with some other register agent. They are saying if I do that my warranty on all the parts will be void. Now they are not answering my call... voiding talking to me. I doubt they have changed the coil. I would not recommend to anyone to go with this company. After you pay them the money, they treat you bad. I have already complaint to the Trane Customer Service. . They are CHEAT and nonprofessional