Useless service

We bought a vehicle in December and had Netstar installed. There is this random alarm that goes off (not the hilux alarm) off inside the vehicle very loud. Roadside assistance who was the only people who assisted us noted this has happened more than once on other vehicles after installation of the Netstar and all we can do is disconnect the battery. When i call the Netstar call centre they just say it is not us and does not help. We disconnect the battery and the alarm still goes off. They never even bothered to inform us when it was installed about anything surrounding the tracker, not even where the panic button is situated. We realised there was a panic button when we frantically searched for this sound and when we called them and they said oh i see you pushed the panic button. Well thank, that's good to know there is one. I logged a complaint in December and still no one has gotten back to us. Yet again this screeching alarm goes off. Toyota and roadside confirmed that is not a alarm that Toyota has installed., it sounds completely different to the normal car alarm. We bought this car from a person we know and he has never had this issue with the hilux, only after the netstar was installed this started to happen. I get an sms too today that said an alarm is going off and to reply with 2 if assistance is needed. Well are they going to send me an sms when and wait to reply when i get ******. This tracker is just not worth it if you get no assistance from them