Netstar - without Stars

My Netstar Early Warning system is actually an SMS system at more than R200 p/m. I had number of false alarms in the past, at least 4 false alarms recently. I received SMS's that said 1 if "ok" or "2" if there is a problem. Guess what? I tested Netstar by not responding at all, never heard from them, not even a phone call. I must say I can't fault there accounting system (5 Stars), they debit my account every month for many years. Do other people have the same experience?