Bad service, *********** staff and even worse mana

Had a problem with all 4 tyres on a new vehicle (20000 km). Was told by the workshop staff at Mercedes East Rand that this was due to under inflation. Had 3 independent assessments done, and as expected the damage was not due to under inflation. The staff could also not explain why the tyre pressure warning system did not work (for all 4 tyres). As the staff were not helpful, we took the issue up with the management. After taking it up with management we realised why the service was so atrocious - because the management was just as atrocious. The branch manager never returned numerous calls, so we drove to the dealership. After discussing the issue again with the branch manager, she said that she would give me a call at 9am on Monday 02/03/2015 to deal with the issue. By 2pm on Tuesday she still had not called (AGAIN!!!!!). Once again I called the branch to speak to the manager. All she said was sorry for not calling (AGAIN!!!) - How many times must a person walk into a rock before they learn? After telling the manager that she was useless as a manager and this was the reason why the service at the dealership was so bad, I was told that I was abusing her! Shame.