Nissan

I took my car for oil leak repair as my car engine use to smoke after driving due to oil leak on 02/27/2010 and was given an estimate of $815 for the repairs. I agreed to do it and was delivered the car on 03/02/2010.
The very day i started experiencing the same problem. I was told they used some brake fluid to clean the engine so i will have the burning smell for few days. But the very next day on 03/03/2010 I had little smoke again from the car.
I took back the car on 03/10/2010 and they gave me a new estimate of $1843.52 for fixing two major issues and another and $700.64 for another issue all related to the oil leak and smoke problem that I came in for in the first place.
All they are gonna do is deduct the money I paid earlier from the bill. But i cant pay for all that repairs. I should have known the entire estimate in the first place so I could make a decision. I would have never done it from them if I knew its gonna cost me so much.
They have got me fixed.
When i spoke to the Manager Mr. Charles Kirby he said "THAT'S WHY WE DON’T REPAIR CARS WITH 150K MILES ON THEM."
I was shocked. My car has 150933 miles on it when I first took it in and 151092 when I went back again.
If it was their company policy or something I should have known it. If i knew they don't like to repair cars with more than 150000 miles I would have happily walked out the first time.
I am just a student and I want my hard earned money back somehow which I spent for nothing. Any suggestions would be appreciated ..
Also please don't even think of going to this dealer for anything because they are just gonna rip you off your money. A small around the corner mechanic would be more honest and would surely fix the problem...
Have a look at the images of the invoices and the ridiculous new estimate sheet given to me after I took my car back with the problem.
The first image is the new estimate sheet given to me after my first repairs. Then there are two invoices Invoice 1 for the initial repairs stating the problem, repairs, date in/out, milage in/out etc.
And the second invoice is when i took my car back with the problem.