Terrible service at Hyundai East Rand

Hi I recently bought a car H1 at Hyundai East Rand, on the 10/01/2020.i was told all checks are done and that all is in order. The car passed roadworthly, don't know how, because after I took the car 2 weeks later we released that the brakes were making a sound. We took the car back, after a hassel they eventually agreed to change the brakes, they only changed the front brakes. Last week I took the car for service that's when we released the rear brakes also need to be repaired. The sales manager is refusing to replace the brakes as he is insisting all was on order. So hyundai quality parts seems to only last a month. The service I got was terrible, it took forever to get my license disc, I only got last Friday. Their service is extremely terrible and the sales manager is rude