[parent control can be ended by task manager]

hi i bought parent control . my phone is not rooted and doesnt have password. my child use it. but today i recognized when i go to task manager i can end parent control without asking any pass. after that i install some app and restart parent control services . never see new apps in app list. this is big problem becasue i use parent control with 3 devices. is there any solution for this problem. thanks