TECHNICIAN MESSED UP MY VEHICLE!!!

A technician on the 14 of February came to install a tracker device on my vehicle and since that day my vehicle cannot start and has been standing. the technician informed me after he was done that the vehicle is not starting but he said it was because of 'low petrol' level in my car. I have been calling CARTRACK since last week and they have been promising me that somebody will come and fix the car. 3 Agents told me somebody is going to call me! The vehicle has been standing for 2 weeks and I have been HIGHLY inconvenienced by this