Car tracker instalment fault

Good day. I join tge tracking compoy for my Polo. The technician installed the device on Wednesday the 5th in the morning at work. In the afternoon. My car wouldn't start, the tecnician came back and adviced me to buy a new Battery. On Friday I bought a new Battery. On Saturday the car wont start in the afternoon. I call them there is no help. Please help me Right now my car is stuck