Poor service and workmanship

Renault Centurion should really fire its management. My wife took a car there and we were told that the clutch burnt. After we were charged R15000 to replace it. Two days later the car did the same thing which was happening before the suppose clutch burning. The car was taken back to centurion where we spoke to service manager who said that they need to test the driving s****s of my wife who has been driving for the past 11 years and all the cars she drove never had this issue. This morning she went for this test drive and the instructor said that she is a good driver. Now they cannot find the issue to the car. So the car is not working and the clutch has issues but they cannot find anything wrong. So now my question is? if Renault does not know what's happening with their own vehicle, then who is suppose to know. Because on Friday evening my 9 months pregnant wife and 2 kids spent almost 4 hours stuck in the unsafe location because the car could not move.

Who should fix our car. Because we have paid the R15000 for poor workmanship. Solution please Renault