Terrible service

VW Westgate gives the best service when they sell you a car but I can’t say the same thing when it comes to servicing the car. Every time I drive above 120km/h and I apply the brakes it shudders (loud noise from the back). I took the car back to VW Westgate more than 5 times for the same thing and they keep on assuring me that they fixed the problem. Today I had to call VWSA customer care to lodge a complaint with them because the Westgate service manager and advisor don’t take me seriously, they’re always passive when speaking to me, they even suggested that I take another car with them. Terrible service!!!!