Terrible (non existent) customer service

Inefficient customer service to say the very least! I've been calling and leaving online queries about servicing my car for the last 4 months and still nothing! I'm hesitant to take my car there without any official booking in case something goes wrong. What will it take for them to at least just attend to my query? What's the point of leaving contact details if nobody will attend to them?!! My car has been parked for some weeks since I'm approaching the 15 000 km mark required for service.