Best way to sue an incompetent main dealer - Advise please

[JensenA]

I've been ripped off by an incompetent Honda Main dealer. Honda Customer service won't/can't help me as they state that "All main dealers are independent, Franchised businesses".
In a nutshell. My car was taken to them with 'faults A B and C'. The car is diagnosed as requiring a new Turbo. A new Turbo is fitted by them, and the car still has the identical faults. Taken back to them, and left there for a week. They seem to fix the fault but are unable to tell me how they fixed it.

They deny any responsibility, they can't tell me how they fixed it. And my argument is that I never needed a Turbo in the first place. How can 2 Turbos exhibit exactly the same faults?

What is my best course of action to attempt to reclaim the money this has cost me?

Mod note: please don't name and shame.

Edited by Bill on Thursday 30th June 22:18

[Butter Face]

Can't tell you how they fixed it? Don't know or won't tell?

I think you would need to prove that the turbo wasn't the issue, which I assume would be hard work now as I expect the old turbo has gone back as exchange for the new one?

Also you should take the business name out of your post or it will get deleted.

[LeoSayer]

Maybe the accidentally refitted the old turbo, not the new one.

Can they tell you what was wrong with the old turbo?