hyundai rediculous service charges

I just requested repairs and a serves from Hyundai East London (for my wife's i20). We got a real surprise. The repairs were not done and the service was only a oil change and it cost R4878.83. When I questioned the cost I got the we only work here run-around. when talking to the person in charges she claimed to have no decision making authority. The headless serpent tactic of dealing with trouble.