Bad service

I complained to them about my alarm. I would be at home and they would phone me and ask me is everything was alright as they got an alarm to say I was in an accident. I told them that my car was in the garage and that they need to change the unit in my car as it was faulty. When they phoned me the next time I had a fight with them and told them they were useless. I phoned their customer service department and told them that I would change to someone else they came and changed the unit last month and I am still having the same problem. I got an SMS to say I had an accident but no phone call.