Bosch has really lost it's credibility

I took my car to Bosch in Pretoria, Gezina for major service and overheating issue. I was assisted by a guy named Eric. After they worked on the car, I was called to collect it. When I started the car, it started shaking terribly. I switched off the car and went to inform Eric about the issue. As we were walking to the car before he could even see what the issue is he was telling me how the problem was not caused by them, they only worked on 1 and 2, not 3 and 4. Eventually, he called the mechanic that worked on the car to check the issue, it turned out there was something they forgot to connect on the car.

A month later there is an issue again with the car. I took it back to Bosch. Again, before Eric could even see the car, he was telling me what the problem is and that it has nothing to do with what they were working on. After some convincing he agreed to check the car. He calls me a few minutes after I had left the station to tell me the same story he told me. So, I ask him how much it will cost to fix the problem he says he has to ask him mechanic to check the car first to determine the problem before he can give me a quotation, yet he called me to tell me what the problem is.

Then he tells me for them to check what the problem is, they are going to charge me R5,600. After telling him that I don't have that kind of money he tells me that he will talk to the mechanic to determine if the problem is what he thinks it is and if it's not then money might not be that much.

A whole week goes by no call from Eric. My colleauge goes to check on the car for me. Eric tells her that I told him to wait on checking what the problem is. Then tells he that they will need to check the car but it's going to cost R12000 for them to check what the problem is, but told her that they were working on the right side of the engine and the issue is on the left side of the engine.