Cartrack is useless.

My Cartrack device was installed on 11/01/2020. Since that time it is not working. I spend many phone calls to them to report it. After 4 weeks they send a person to my house. He spend 1 hour looking at the car and then say it is OK. I must drive for 3 km after 1 hour. I have driven already 400 km and it is still not working. I have send messages, phone call them yesterday again. They say they will come and fix it. I don't when it will be done. I have paid them for services last month, but no service was received. To me they are useless in repairs and complaints.