Poor Service from Mercedes

The service is becoming horrible.

Since between July and August I have booked my vehicle for repairs. The first time it was returned because spares were not available. I got sms that the parts were now available I must now take it, which I did. Later on was told car won't be fixed I must collect car because they did not get the spares. Keep in mind this was second time around. A week later I got another sms confirming booking and part availability. The same thing happened the car was returned not fixed. Now I got a 5th sms to take in my car on the 15th. Shocking I'm told again that the parts are not available. Five times, this is what you get for buying a Mercedes. I paid a premium hopping for better service. Very shocking and disappointing to see what Mercedes is becoming. Immagine booking in a car to fix a door 6 times and they still can't get it right.