Motor service

I have a problem on mechanical repairs done on my car where the service provider **** to me and now, after a few months, the same repair has to be done again costing me more expenses. I took photos of the wiring that they attach with cableties under the car , after driving the car on a dirt road the wiring scratched and the car started with problems they fixed it kind of cuase the same day after I piced it up wiyh everything left open the car did the same thing, well I drove it for a wile cuase I had to after a second dirt road the car dit not want to accelarate and I asked them to please sort this out !! After some hash words he send two guys to do diagnostics on the car after they read the error code the one guy started pulling out relays and as I am watching him he turns the relay around and the competerbox starts smoking !! He does not want to fix this now!! There is alot of customers that is complaining about his service!! And this is not my only comlaint from the start he gave me one quote of R4200 to fix the car after he opend the car he said now it will cost me a extra R24000.00 after that the car still dit not work and he asked me to buy extra parts and he done this 5-6 times after the first quote ,the car was there for 3 months we had it back now for about three month in that three months it went back and forth to his shop!! Now please help me He says I can do what i want he will not fix the car. What recourse do I have.

Thank you,