Mercedez Rosebank failed to help me

I purchase a Mecedez C180 with registration FV 00 KS GP at Rosebank.

The car had inconvenience after few weeks after purchase and as I was told that should there be any problem with the car I may just sent it to the nearest dealership and the nearest for me was New vaal. The car was vibrating all four sides of windows shaking its was making a bad noise. I sent to to new Vaal for a number of times they would book the vihecle inn and call me after fee days and say the vihecle is ready and fixed but when i drove the car its was still making a noise. New vaal they did not help me untill the cat we nt out if warranty even when i called mercedez benz head office they insisted on getying hold of a New vaal DP which i did but he onlt sad that " the vihecle is going according to mercedez benz speccification if which its wasn't untill the car was out od warranty the New vaal book the vihecle inn again after that they sentbme an email stating that the vihecle was on an accident and its was not repaired according to Mercedez benz speccification and i must take back to Rosebank. I had a meeting with Rosebank management and they sad they will fix it i must give them a chance and i did gave them a chance because i have sent tue car to tgem more than five times but they couldnt fix it untill today and after sending them email they just ignored me and im still paying for the car and its still making the noise and vibration which is the opposite of Mercedez. Rosebank themself did not help me either as the car was on an accident and they did not see fit to inform me about the accident. I am so dissapointment with the vihecle as this Brand mercedez it's shouldn't have such problems even when they call their technician they did not help me with the problem. Now i need them to give me a new car or tabe back their car and refund me or terminate the contract.