They probably haven't called you back. As stated, it doesn't work for me. I placed this caller in my Ignore contact. The calls are now silenced, but display on the screen. And they can leave voice mail. Maybe T-Mobile disables the caller blocking feature? But I see no more function in this iOS 7 feature than I got in iOS 6 by assigning the caller to a silent ring tone. In iOS 7 if you block a caller but don't assign a silent ring tone then the phone rings when they call. So obviously caller blocking isn't doing anything.

This caller is really annoying. It is XM Satellite. The trial on my new car's XM Satellite subscription runs out next week. They have been trying to get me to renew almost since the 3-month trial began. Pay day is the day before it expires so they will just have to wait!