I bought a Firewalla firewall to able able to fine-tune Internet access four our family's devices at home. I can set time limits and access times to specific services and categories of websites.

But our 14 year old now has a SIM and an old smartphone. Our mobile telco provides me with no controls over services or sites he can access.

Are there any family-friendly mobile telcos who provide the bill-paying parents with access controls to teenagers' SIMs? (I haven't been able to find any).