Faulty Unit

I had my car installed with tracker on Friday 18 Dec 2015, on monday I spoke to 4 different agents then. It was discoverd the unit is faulty and it has to be replace by Mototrace supposendly. on Tuesday. I folowed up today stil no contact from either. Its not even 7days and already their SLA aren't met. Its breach of contract and I see a clause of 20days to terminate, I can't have my instalment go off on the 1st for nothing but complains and constant phonecalls. Its xmsas weekk and I don't want festive holiday to be an excuse for non delivery because my sale was delivered very quickly. I'm really disappointed!!