I've read emails relating to Parental control for restricting access and find it's not as effective as I hoped.
I've signed up for a 6 month contract, if this issue doesn't get resolved by then, I'll be forced to sign up with another provider who'll give me the privilege of an effective parental control system.
Welcome to the Community!
Please be advised that 'Parental Control' is an advanced feature of any modem/router in which the customer has the option to use or not.
You may refer to these links and Community thread for reference: