Bad after sales service

I bought a brand new Renault Duster from Renault Klerksdorp, after 7500km on the clock the vehicles brakes started to give trouble. Renault then replaced the brake pads, after another 7500km the problem started again and they replaced the discs as well as the pads. Last week they serviced my car (45000km) the same problem again. Long story short the rear brakes was the main problem, they fixed it but the now they say its actually the wheel bearing but they cant supply the parts now because of the warehouse that's moving location and they can only help as soon as they are done moving or unpacking the warehouse. I have locked a call with their complaints line and one of their people phoned me and said they will get back to me, they never phoned back. In the meantime Renault gave me one of their vehicles, they now phone me every time to bring the vehicle back cause according to one of their sales people they sold the vehicle (this happened twice). These people are ******ing me around.