Incompetence from dealer

• I took my car in for service on Monday and when it come back it started overheating on Tuesday morning on my way to work. Called their offices and spoke to Lesedi she said I must bring the car back and I asked my boyfriend to take it there. Tumelo tested the car also took it for a drive and couldn't find any issues, there were 3 guys around him talking trying to find the issue and not coming to any conclusion, they called my boyfriend back. He asked them if they didn't diagnosed the car and they then did it in front of him thats when an error HVAC popped up my boyfriend asked for a printed out but whoever who busy delete the error fast and said the car is fine and he must take it and should it persists to bring it back. He then drove the car to pick me up at work something happened. Wednesday morning he took it back in he was not getting any assistance till around 10am after he spoke to service manager Shaun to tell him the issue. Tumelo and Shaun then tested the car and found that the water bottle lid was faulty as it could handle the water temperature and my boyfriend bought the lid he was told the car should be fine. He drove it to pick me up at work and it was worse as it overheats coming and going back. Thursday morning we took it back and we spoke to Shaun who said they are not picking up any issues and I showed him the video I'd took the previous night. He was like " I will ask my foreman to test it again" I told i was not happy with the service i am getting and this overheating will ruin my car he said " if the temperature gauge is not on the red bar its still safe but he will check the car again as they are not finding anything". I told him i am missing work to get this sorted. The whole day Thursday my car was there no communication from anyone at the dealership i had to call after 1pm left a massage as Lesedi was busy and I called back after 3pm spoke to Shaun and my car was untouched till then. Lesedi calls me back after 4pm tells me they will call me once they check it. I told her I need my car back Friday. Today is Friday 10am noone has called for any updates i am left in the dark. Its very shocking that a whole VW dealership is unable to find fault in an overheating car. And I've been servicing the car there for over 4years now and this is the treatment I get.