Car service

What exactly is the reason for making a booking for car service ?. Got here at 09:00 but its 11:23 and they have not even started on the car yet. Wanted to know what is going on but was told with attitude that there were other cars before mine but funny enough cars that came in after mine were attended to before mine. This is not he first time his has happened and it is now starting to annoy me. I can not recieve such poor appauling service for something I am paying for ????