Have you set up Anti-Theft as here;
It is quite odd that it keeps being disabled, for us to even attempts at pin pointing where why or what could be causing this behavior could you answer the following questions:
1: What device is this on, Samsung galaxy S3(mobile telephone) or Samsung galaxy tab 3 or?
2: What android version is your device currently using?
3: Would it be possible for you to provide us with a list of the installed applications of your device, as it seems probable that another app is conflicting or stopping our product.
4: Did our software ever work properly on the device?
5: From where was the software downloaded*installed from?
May I know which screen lock method you are using at the moment (password/PIN/pattern/face)?