Instant Lock Does Not Work

On the family.norton.com website, Instant Lock was shown to be ON for my child on all of my devices.  However, using his password, I could log onto the computer without any restrictions.  Called Norton chat support, and the agent uninstalled and re-installed Norton Security.  This worked for about 2 days, and it stopped working again.  I have changed all of my passwords and I am sure that my child was not able to log onto Norton or as the administrator on my computers to change any of the settings.

Any suggestions would be much appreciated.