CHM East Rand Complaint

My car has been to CMH East Rand 5 times for the same problem and they couldn't seem to find what was wrong. All they do is run a diagnostic test then throw their hands in the air and say they can't see any codes therefore there was nothing wrong with the car. After the vehicle was by them, I noticed a loose connection in the engine bay and fastened it, since then the car has been behaving itself. CMH East Rand contacted me after I had complained and they asked me to bring the car back for the 5th time and they would give me a courtesy vehicle, I agreed and dropped the car off (I did inform them that I might have found the problem, but they insisted that I still bring the car). I was contacted and asked where my service log book was, I informed them that it should be in the car, they then said that they would check. When I arrived at CMH East Rand to collect the vehicle, I asked if they found my service log book and they said they still need to check, all they did was look inside the car, I said to them, why would I take it out, I never have and never would, so they had lost it. To top it all off, when I had left CMH, I saw that my windscreen had a lovely large crack in it!!!