Time limits and time curfews do not work

My children can log in to their accounts at any time, even during times when it should be locked. I have the time limits set to 1 hour. They get a 15 min warning and the get as many 1 min warnings as they want. It is not locking them out after multiple warnings. I have passwords set up on their accounts, but that doesn't slow them down much. They have been on for 30 extra min before I caught on.  And they can log in during curfew hours and still get the same 1 min warning. 

I checked to make sure I have the latest version. I have wind 7 and chrome and ie 8. 

I do not like the idea of giving them 3 warnings as I read on some other posts, but I would take 3 over unlimited at this point. 

Any Advice?