Bad Service experienced at Mercedes Benz

Sent my car for Service on 11/04/2016. Got a call late saying there is Time Chain pulling and needs to be fixed but require permission from Pretoria and the process can take over 3 days to get the car fixed. I informed them I need courtesy car and there contradicting statements both from Advisor and Service Manager (Pier). They refused to give while I am paying for the car through Mercedes Benz finance and still under maintenance. Contacted the head office and was informed that the branches needs to resolve this. Till now my cat hasn't started the process of being fixed and still no good feedback on what they will do. Am stranded, paying lots of money for a car with a premier brand like Mercedes Benz yet the service is this bad.