Fidelity Adt's poor service to thier clients

I am very disappointed with the response and service I have received from fidelity adt. I they had contacted me about testing my alarm system, it was established that some of the sensors in the house don't work. I than called them a week prior to schedule for a technician to come to my premises and fix the problem, a visit was scheduled and thier technician was meant to call and established a time that never happened, I called them on the day the technician said he was at my premises yet he never showed up as I had people working on the premises that day. I than called again to schedule a time and I was told that he will come after hours on the Friday, I waited and waited and no one contacted me. This is ulter disrespectful for me as a client of theirs and proper business practices should never be conducted in this manner. Should anything happen to me or my family will they respond in time will they even answer my alert call. If they can't even come and fix something they will charge me for anyway?