Billed but fault not fixed

Had a car breakdown sometime in March 2017, brought my car in to Bosch for repairs and service. After a while i had to do a follow up on the progress of the car, service advisor told me that there's a part that needs to be replaced in an engine so they waiting for it to arrive from overseas. Weeks went by with no progress, then the consultants adviced me to replace the whole engine because they've been waiting for the part but not winning.

They then requested the details of the insurance company for the extended warranty because to replace the engine was going to cost about R70000, the insurance was going to pay about R40000 to R45000 and I was going to pay the differences which was about R25000. I gave them a go ahead to do the work because I was starting to be desperate for the car.

The 29th April 2017 I was called to come fetch my car because the car was ready and fix. Took the car for a test drive, the car was driving but didn't have power. I was told to drive it for the weekend and bring it back on Monday, I brought the car back after realising that the air conditioner was not working, the widescreen spray not working and the water bottle will go empty in few days and the car will overheat. Few days later I received a call from a service advisor telling me that they had taken the car to BMW and they had repaired the power problem, so I have to pay half of the invoice which came to R2200.

Few weeks later I requested my old engine, I was told to pay R1860 for the top which I didn't pay and got only the engine block with no top. I continued to drive the car that kept on overheating then I would bring it back to Bosch. They will check the car and won't find a fault.

Beginning of November I left my car for 3 days on the same branch for the same problems that I've been experiencing since they've replaced the engine. Again they were supposed to fix the air conditioner, widescreen waterspray and water bottle that goes run in 2 days. I was called to come collect the car because all is well. When I got there the air conditioner was not done because they couldn't do it. They had replaced the water cap, poured anti-freeze and replaced the waterspray for the widescreen. I checked the following day and the water was almost dry and there was no anti-freeze on the water bottle. The remaining water on the bottle was clear instead of green hence I was adviced that they poured anti-freeze. I still had to pay almost R2500 for return job.

I just want to know if this is done on purpose so that I will keep on paying or is Bosch not interested in fixing the return job.