Cox WiFi app

Sometimes when I block my children’s devices from the internet Using the cox WiFi app,  they can still access the internet and use their devices. I’ve assigned the device to a profile, I’ve set the hours they can use it and so on, however their device can still use the internet? What’s going on? I can look at the app, they can be in downtime or meet their daily hour limit, but the router doesn’t disconnect the device from the internet? How to solve this please?