I use Netstar and my car sometimes gives a false signal. When they get through to you they ask you to confirm your number. Quite a few times I have missed their call and that?s it. No 40 Calls to check if u are okay. I mean if I?m hijacked that would be the end of the story. Yes there is some benefit to having a tracker but with this 2 missed calls and they continue with their business I think we are just a source of income