Terrible service

I bought a brand new car on the 14th of August 2017, within a week, a brand new car started giving me a problem, i informed my sales person who advice me to take back the car to the dealer, the car was sorted ill say for a day because i did not use it for the next 2 days, when i started using the car, its started again, i tgought maybe taking it to a different branch might help, i took it to Edenvale, which they assured me the problem was fixed, but on my way back to the office, the very same day, a brand new car started again, i contacted my sales person again who said i must bring the brand new car to their dealer again, which they called asking to deal with the car the whole day and night bcz they failing to resolved this problem with their car. I had to take a taxi home, got home after 8 at night, i have been asking this guys to change the vehicle and give a another car while it was stll less than 30 days old. I am so disappointed with this RENAULT brand, what is the point of buying a brand new car if it still give you hustle, please assist me guys, have not even started paying for my 1st installment for this brand new RENAULT car but im tired of it already, my older brother and 2 of my friends wanted RENAULT cars but i have convinced them otherwise. Please help me resolve this issue, im so frustrated.