Paying for an attempt to fix car

I took in my work Bakkie as a tow-in because of mechanical failure. The car was kept for 2 weeks before any correspondence from the service provider. I called to ask for the progress, they patched me to the workshop mechanic who asked me what lead to the failure and I told him in detail. A week passes and I call back in to ask again, no updates from them about the car I have to keep on chasing them, with that a quote of 41k is given to fix the car. I call to verify if they have thoroughly diagnosed the car and they agree. 3 days later we receive another quote for 9k for other parts to be changed. We give them a go ahead to continue fixing the car. A week later we get a call that the car is almost finished and being tested we will get a call from the the following day, but to our dismay no call the following day. We went there with my colleague to check what was wrong and we were told that the piston made a hole in the engine internally and we need a new engine. Now we have to pay 50k for the attempt on fixing the car of which a dispute occurred.