T-Mobile really REALLY needs to add a service to allow customers to block anonymous calls, where Caller-ID is withheld.
I've read the T-Mobile support article on this, and it says T-Mobile can't, is not allowed to, block such calls. This is FALSE.
T-Mobile can certainly offer such a service. It is allowed by law, and other carriers offer it, and have offered it, for years. It's an optional feature, that each line owner can opt in to. Some simply block the call or send it to voicemail. Some are more elaborate, like AT&T's Privacy Manager, that asks the caller to identify themselves and lets the call ring through if they do.
The article says it's the right of people to withhold caller-id when they make their calls. Absolutely true. It is also my right not to receive such calls. We need T-Mobile's help.
This is especially necessary for Iphone users. On the iphone, you can block any call, as long as it has a number. Anonymous calls don't have a number, and so cannot be blocked by the Iphone's native OS, nor by any add-on app. Despite being asked by it's customers for years, Apple has decided that all Iphone owners MUST have their phones ring when an anonymous call comes in. Think about the perverseness of that: Apple will let us block anyone, except the people who want to conceal their identity from us. This is not a technical or legal problem for Apple (or T-Mobile). It is 100%, Grade-A hubris.
So PLEASE, T-Mobile, offer this service. I'm hopeful, now that you're offering your Scam-Blocking feature (which blocks calls!) that you're now on the right track to give your customers back a bit of control. Your customers will thank you for it!