Poor car service

I took my car to Valley View Car care clinic on Thursday morning 07:00. Christo assisted me through the following process - I received a phone call from Christo stating that the gear box fluid as well as filter needs to be changed for R6000 as well as the wiper blades which I asked them not to attend to. I gave permission for them to continue. I received a phone call stating that my car is fixed. I paid R6000 and when I was 800m from the Car care clinic my car presented with exactly the same problem. I turned around and took the car back. My car was then left again at the Car centre for repairs on the Friday and I received a phone call again stating problems with my wheel bearing, nothing being said about the gearbox which was the actual problem. I asked about the gearbox and it was reported that the car is fixed and was test driven 3 times by 3 different people. I went to fetch the car and for the 2nd time the problem was not fixed and the car presented exactly the same. Christo also did another test drive after I said the car is not fixed and his words was "Yes but it is not that bad and is fine when gears are changed manually." I expect my car to be in working order after paying R6000 and not to drive an automatic car in manual mode just because they can't fix it properly. I took the car back again on Monday as I did not want to lose the R6000 that I’ve spent already on fixing the car so I thought to give them more time than the 2 days where they could not solve the problem. I received a phone call on the Monday stating that it will cost me R37000 to get my car fixed. Christo stated that the diagnostics was clear on the Thursday and Friday and when I fetch the car on Monday he showed me 1,5 A4 paper of problems that was picked up during the diagnostic test. When I asked him how is it possible that the diagnostics was clear from any gear box problems on Thursday and suddenly on Monday all these problems are shown, his response was maybe because the car was driven too much from then till now. My car was used to dropped me off at work and driven back to the car care clinic, not sure why if the clinic has their own vehicles to take clients to work as stated on their website. When I ask how do I know that the problems were not caused while working on the car he just shrugged his shoulders. I asked for a refund or at least some of the money which was promised to me by Christo on the Thursday and on Monday he just told me to speak to his supervisor who was also very unhelpful and not willing to refund. I asked for the contact number of the owner and I was told they’re not allowed to give it to me. I also asked on Monday at 07:00 to be picked up at work at 16:00 and phoned at 16:00 just to clarify if someone is on the way as communicated, only by 17:00 someone was on their way to pick me up at work, I organised a lift as I was not able to wait an hour as I also have other duties to attend to. I am extremely unhappy that I had to pay R6000 for the wrong diagnosis of my car, fixing something that clearly was not the problem and not even get some kind of refund and they expect me to trust them when they say my car will cost R37000 to be fixed after telling me my car is fixed twice before when it wasn't. These people obviously didn't know what is wrong with my car and how to make a car diagnosis, their service is very unprofessional and plenty of empty promises are made. I definitely would not recommend this service!