Purchase of vehicle

I bought a used Navara from NTT Nissan Potchefstroom in June 2015<br> Since the day I started driving the vehicle I have had problems with it.<br> The vehicle has been back to them twice and still there is a problem with a vibration and drone inside the vehicle,They collected the vehicle twice and the second time they have had it for almost ten days.( Needles to say the problem was not sorted out)When the vehicle was brought back the second time the left front bumper was scratched- It was pointed out to their driver Bruce - (their comment was get a quote and we will pay for it)<br> The used car sales manager told me that they took the vehicle to a repair shop as the Nissan workshop and parts was to expensive.I have been phoning and texting them with all empty promises and nothing happens to sort out the problemI took the vehicle to Tiger wheel and Tyre and they confirmed that they tires are out of round and that the wheel alignment was out.They said the tyres was never rotated and that the tyres on the vehicle is the wrong size. The spare wheel is a different size and rim to what is on the vehicle: size 17\ with 16"on the vehicle <br> The worst of all is Nissan SA is not even prepared to help"""