If you own an android, root your phone, install avast and install their anti-theft as root. It then will not be removed, even on a hard reset. It becomes difficult to remove as there is a password and you can lock it down a whole lot. I can track my phone any time, even with a foreign sim card. As soon as it connects, I can find it, because with root, I have control over GPS. All via their website or text messages.