CarMax Sold me junk Chattanooga Tennessee

 I found a car that I liked on Carmax's website and the sales team had it transferred to Chattanooga for me. I got approved for financing and found out what my down payment was. It started off really good. The day my car came in, my sales woman said it was ready for me to come test drive and decide whether that's the car I want. I go in and test drive, the check engine light pops on. I really liked the car and I was assured that the service department would take good care of me. I went ahead and signed and paid my down payment. They put me in a loaner vehicle. This is where all the trouble begins. Initially my car was in the shop for 13 days, they claim that they had to take it to Knoxville to the Mercedes dealership to fix it. I was very upset that it took that long. I then took possession of the car. It was nasty. Greasy door jams, dog hair all in the back, dirty motor and wheels. I called back up there and I was assured they would detail it the next time I come in. Well they must have knew it was going to be soon. A few days later, the car started stalling on me in intersections and losing power when I drive it. A couple of days after, my whole car started smelling of straight gasoline. We had to drive it with the windows down. I called the service department and they told me the soonest they could get to my car was July 4th. So I drove it until then, almost getting into four accidents due to the stalling and losing power. I show up at the dealership on my service date and they give me another loaner. 11 days later,they tell me my car has been detailed and repaired. I go to pick it up and the car was even nastier than when I brought it in. It looked like someone had been mud bogging in it. My door jams were still nasty so I went back in and insisted this be fixed. So back in the loaner I go, and told to come back in a couple of hours. I come back, they said they could not find a problem with my car. It was still acting up and I checked the door jams and I wiped nothing but black off it. I marched back in there demanding a manager. I spoke with a manager and they said they could appraise my car to trade in. Really? I maybe have drove this car 14-15 days... carmax has a 30 day guarantee. I'm still well within my 30 days. They appraised it from $500 less than what I paid and was told that I would have that on negative equity on a new car. I told them it was absolutely unacceptable since I was sold a lemon. Today, I call to see what can be done. I spoke with the general manager and he basically told me that it's all in my head but he would have service look at the car again and that only if they find a problem they will fix it. I informed them I had another mechanic that is ase certified to look at it and I was told it was a transmission issue. Today is now day 9 without my car again. I told them I demand resolution by Friday, otherwise I have to seek arbitration. I called my lender about what's happening and they are not happy about the situation. So I continue to wait. Whatever you do, do not do business with car max in Chattanooga,TN. I should have went to the dealership my brother or cousin worked at in the first place. I'm very angry and do not feel I have been done right. I was told if I called corporate, they would have the same general manager deal with my problem that isn't aiding me in resolution. I feel stuck paying for a lemon with an extended service plan that's a joke.