Bad Service from Cartrack

I called the Cartrack client service centre in order to add another vehicle to my existing fleet contract with them. I also informed the agent that one of the vehicles on the fleet has since been written off and the agent asked his manager about the situation. I was informed that I must continue paying for the vehicle even if it has been written off. Either way, I continued to make a request for the addition of the new vehicle. I was given an appointment for installation and just 5 minutes before the time I was called that the technician is no longer coming and they promised to arrange a different technician. I received an SMS stating that the technician will be on-site within 2 hours later and that too never materialised. I thought to myself I can't give them my business anymore and I did inform them when someone called to make a follow several days later. Since then they harass me with calls on a daily basis.