Disaster service!

I have been with ADT for a few months and it has been a miserable time. The alarm system always has issues, where I receive sms’s about a low battery. This week my new tenant was struggling so I called for a technician to assist. They left us with 2 invoices and not much help because as soon as they left, we received another sms for low battery then around 8pm one that read “power failure”. When I called for urgent assistance because the alarm was off, the response guy kept getting lost and calling for directions. My issue is that my understanding was that this is their alarm and I’m renting it so every repair is their responsibility, so why now am I being charged a call out fee and being told to also pay to replace a battery. Now my new tenant has no working alarm because I have just been told to wait till the morning to log a call for a technician to come. So essentially im expected to pay R573 x2 or every single time their alarm is faulty. Why is that my problem??