PURRFECT AUTO SERVICE I got taken for $1,200, car still doing the same thing -Taking them to court Las Vegas, Nevada

My check engine light came on on my Dodge Intrepid so I took it to purrfect auto on W Ann Rd. They said the diagnostic would cost $85 and they would apply it to the repairs. The manager called me an hour later and told me the egr vale and solenoid had to be replaced and it would cost $1,200. I thought it sounded high but my wife told me to just get it done, she didn't want anything else to happen to the car with the light on. Later that day we picked up the car and 5 minutes after leaving the shop the light came back on. I called them back and they told me to bring it back the next morning. The next day they asked me to leave the car there for a couple of hours. After more than 5(!) hours they called me with more bad news: apparently some tube had to be replaced and the cost would be an additional $450. I was furious. Why did i have to pay $1,200 the day before and now find out it would cost even more?! I argued with the manager, but he insisted that he was giving me the part at cost. As i later found out, he was (again) lying: the part costs $148 at the dealer as i later found out. I told the manager that i want my money back and i no longer trusted him. He said that he can't authorize a refund and everything he has done was legit. I don't think so. I feel that all the repairs done were unnecessary and I'm entitled to a refund. Then he told me to take them to court, which is exactly what I'm going to do. I just wish I had visited this site before I took my car to this place.