I had a new heat and air unit installed 7-2011. It was damaged during installation in two areas that affect the functioning of the unit. 2 sensors controlling how the unit cuts on and off were damaged by technicians during install for not following installation protocol, this has caused the unit to cycle on and off repeatedly day and night when the a/c is running, causing irreparable damage to major components of the unit. Also the blower door on the unit under the house was broken since installation, effectively bypassing the $1500 filter we had installed with the unit by drawing in air to be delivered to the house straight from the crawlspace. Called the company to come back and correct issues, but they never came back out, yelled at me scolded me for over reacting, told me as long as there are other people without air I would be put to the bottom of the list to be seen, and besides "you have a warranty". No one ever came out even after repeated phone calls, and broken promises to come out. One year later called for service when first turned unit back on for the season and was still cycling, company said was coming out but again no show several days. Called back and asked them to do the yearly maintenance I had already paid for. Finally, after almost one year later, they came out. I showed the owner what it was doing, he had no clue what to do after about 4-5 hours. He unplugged a sensor and told me to watch it. It ran ok for a bit, I told him, he said would order part. Over a month later had not received part, and was rude and evasive and hung up on me. During all this I did call other companies to correct these issues. Not one of them would get involved because they said it was an installation issue, and they did not want to assume any liability. Trane advises that any problems occurring during the first 2-3 months of operation be handled by the original installer. 7-2012 I called several more service companies, and found one to come out. Cost me $90 just to show up. The technician knew exactly what to do, diagnosed the problem and was on his way in less than an hour. He told me the sensors were most likely damaged during installation, and that they should have been removed to prevent that. He ordered the parts, said the blower door was not covered and would have to be replaced, would need to get installer to repair. Now, when the parts came in, the office manager called me to get additional warranty info. We discovered Air Today had taken my payment for an extended warranty, but had never filed it with Trane. This is a huge problem. If not registered within 60 days, a warranty is not upgraded, and this means that instead of a 10 year parts and 5 year labor warranty, I have a 5 year parts only, and to add it now would mean the unit must be inspected and any broken components would not be covered at all, and nothing would be covered for 90 days. So today I called the new company to come out and install the parts on Wednesday for a cost of $210. I never received a fully functioning, new damage free heat and a/c unit as promised and guaranteed. I have a unit that has wear and tear well beyond its age, and the end life of the unit is most assuredly shortened. Not to mention if air fails, we are without, it takes more time to fix, and may not be covered by warranty according to Trane. What is the best solution to this problem, ideal answer would be a refund, from the installer. What are the chances this would go in my favor in court? Should I have a lawyer? What would that cost? Any additional advise?

Optional Information:
State/Country relating to question: South Carolina

Already Tried:
talking to company, filed complaint with BBB got nowhere, called other service companies, reluctantly investigating court options but can't continue to pay for goods and services not delivered