Bad Customer Service

Why is it that when you are buying a car you get the best service but once you take delivery of it, the dealership doesn't care about you or your problems? I bought a brand new VW Polo TSI in January 2015, not even six months down the line a knob on the radio breaks and it is such a hassle to have it sorted out. A job that could take 30 mins, McCarthy Volkswagen in Garsfontein wants me to book it in for the day, as this is their process. What a joke. What an inconvenience? The workshop supervisors attitude is that if I want to complain, I should do so, but that is the way they work and I have no choice but to have the car booked in for the whole day if I want this to be fixed. There was also another customer there at the same time, he had brought his vehicle in, about six times for the same problem. I think that they should close down this dealership or send their staff for some training on customer service.