Bad Car Service

I love Audi and it hurts to write up a complaint about their service, I am extremely disappointed at the service provided by Audi Revonia, 3 days ago we took our A3 for a major service of 120000KM and service was done on the car. This morning the car showed a coolant error, we opened the bonnet there was no antifreeze in the coolant bottle which now is casting a big doubt that the service was performed, makes you wonder what else was not done right. The severity of having to fix a seized up engine is overwhelming I am feeling cheated with this occurrence and the emotional scar it has left me. I mean "THIS AUDI"(Vorsprung durch Technik)