Audi, German precision does not exist.

Audi A1 went into Audi Fourways to have the timing chain changed. Since then the car has been leaking oil, it has gone back to them three times. Firstly the chain was not synchronized correctly, then the seal was not put in, the last time they had the car for two weeks. Came back still leaking. Emailed Audi SA and Fourways no response at all. I am vert disappointed in Audi, what happened to German precision?