Not happy with ADT services

I installed the alarm system in February at my house and it was working fine until last week when I tested it and they were not responding. I called them to find out what why are they not responding and they told me that they will send technician in Friday n nobody came. I asked them which days must they come as I am not always home. They called me today n I told them I'm not home. I called to log a new call n they telling me that I will hv to pay R590 for technician to come and fix the alarm I feel it's not fair why is it my fault that the alarm is not working as they will be deducting monthly premium for services that they not even providing.