questionable repair work and unfair treatment

I took my car to Menlyn Auto for repairs after damage on my cylinder head caused by a different BMW approved workshop which BMW SA agreed to 50% towards the repairs for. I paid a total of R39 000 for the repairs but a few weeks later my car started leaking coolant again and having a cold-start. I then took the car back and I was told I have to pay another R14 000 for replacements of some parts of my cooling system. it's pretty clear these guys are doing a trial-and-error repair and can't pin point problems. They replace parts until they replace the one creating problems while we are footing the bill. After having spent R53 000 I still had to fight for transport top take me between home and work and still was told there are no driving and if i want a courtesy car I will have to pay R1700 a day by their workshop manager called Hugo.