@ Red,
I would DEFINATELY get a second opinion. I traded a computer a few years back ( a well spec'ed one, at the time) to a mechanic 'friend' of mine, who needed one for his garage. He told me that there was a radiator problem, but gave me the part that would 'fix' it. I know next to nothing about cars, so I did it.
I couldn't get 5 miles before the car overheated and died. It was a nightmare. It made me late to interviews, etc. I had a REAL friend of mine, who's an ASE certified mechanic, look at it and all he had to do was remove the carb to inform me that it had a blow piston and a rod knock. The oil pan hadn't been changed in so long, the oil within it was a solid mess of goop. My 'friend', who is a mechanic, 'claimed' he didn't know.
I never got reimbursed for the car and it was eventually towed by my apartment complex, who claimed it was abandoned. They wouldn't refund the money it would cost to get it out of storage, so I left it. I haven't had a car since.
I would look into it, 'cos I know for a fact that independent garages will 'break' things to make you come back. I know it's hard to compete against the Name-Brand Facilities, but that's still unexcusable. Odds are, it will cost more to sue, but a place like that should have its doors closed. It's obvious they're in the market to only rip people off.
If they give you any grief, a high-powered sniper rifle can work marvels in such a situation. :lol: