Looking forward to hear from y6

I bought a renault duster at autopedigree in benoni in March this year. My problem started on the 21 of the same while driving on a 120km/h speed the car decided to cut power on the freeway while in motion took it back to the dealership then it was taken to Renault , it came back looking fine, and I was told that maybe the pipes were blocked since it has not been driven for a very long time. Easter weekend I went to Bloemfontein then started again I have never been so humiliated in my life just imagine driving a car that stops on while driving. I reported the matter again it was taken to Renault stayed there for more than 21days cause I was told that they would order a part that they diagnosed it as faulty. Now it's back, engine light is on still cutting power. I don't understand what was fixed but exhaust have been replaced by a private company whom Renault is working with, I reported the matter to autopedigree manager since he said he'll come back to me. I don't know what to do anymore cause this car is not performing to my expectations and they failing to fix it. All I want is for autopedigree to cancel the contract.I DON'T WANT THIS CAR ANYMORE