I have a relative who keeps calling a premium-rate telephone number. I want to block the ability to call this specific number because it is able to rack up a very high bill in a matter of hours.
They also have a feature phone (dumbphone) where as far as I found out it is not possible to block a specific outgoing number, nor do the phone carriers in my country offer the ability to block the calling of premium numbers (or the calling of one specific number).
My first option is to buy a cheap smartphone and somehow block this one premium number there. It would be best if I could block the number directly in the phone settings (parental controls or something similar?) and lock the setting with a password.
The second best option would be to install an app that can again block a specific outgoing number and lock the setting behind a password. They would not be able to root the phone or do anything similarly technical to circumvent the limitation.
My third option is to take the phone away altogether, but it's used to stay in contact with other people, so this is a bad solution (albeit one I must reach for in case the other ones fail).
What solution would you recommend to block a specific outgoing phone number? Does some version of Android have parental controls with a block of outgoing calls? Or is there a good app for it?