"brand new" car

I bought my car in July 2018 a Renault Kwid 2018 with 64 km on the clock. This "brand new car" has gone in on 5 occasions to be fixed and is only 6 months old. I have advised the dealership regarding the intermittent issue received as there has been more then one ( I have sent the list of issues to dealership - where my engine light came on within the first two week of owning the car and more ) and it was made to sound like i am lying or i do not know how to drive a car. When driving the car, the car slows completely down and then shoots to the front it loses power. This has happened on numerous occasions and every-time the car goes away, It drives okay for the issue to occur shortly after. It is clearly a manufacturer problem because they do not know how ti fix it , however, it was made out to be as if i was lying about the issue and if i have time to waste. I have allowed them to fix and do whatever they need because i have grown attached to the car and fuel consumption is perfect for me. The car broke down on Monday and had to be towed away as this occurrence happened twice after each other where it has not before and the second time was so bad that the car shaked. The car has been with Renault now for the past week and they were doing test to tell me that they've been driving the car for two days and nothing happens , until it finally happened to The Foreman at Renault and it was finally seen that i have not been lying about the matter . I have explained that i need my car for work purposes and i drive late at night and on a dangerous road, therefore i cannot have a car that is unreliable as i am a young single mother and cant be in danger due to a car that might switch off , cause theres no telling when it will happen. Why am i paying R3400 for a suppose to be " brand new car" ? To not have these issues. They want to fix the car again and give me this car back. Where i have confirmed that i do not want a broken car back. they either need to cancel the deal as i am well within my rights and it has been confirmed that it is a problem with the car that is intermittent or to give me another car, but the sales man rather said on the phone call that i need to trade the car in, and i have to pay R1000 more for a faulty car that they sold me which is ridiculous! Why must i suffer and phone and have to make threats in order for them to assist me. They are so afraid of actually helping me or giving me a new car or cancelling the deal. Why? Would they rather risk a customers life and that of her sons? This is my first time buying a car and its been the worst experience ever!! The regional message was informed of these issue as it was a struggle to get his details as someone in Paardien Island stated he does not have the number which is more bad service !!