Calls from other devices using T-Mobile not working

Hello all,

I use an iPhone 6s on T-Mobile, one of the features presently unique to T-Moblie and Sprint is the capability to make and receive calls thru another Apple device such as an Apple Watch, iPad, or Mac when the iPhone is off. I would like to use it on my MacBook Air. The way it should work is when on the Mac and signed in with same Apple ID as the iPhone the feature should offer the option of upgrading to WiFi calling producing a six digit code to be entered on the iPhone, I don't get that option.

All settings are correct on the iPhone where in settings, the phone, the area allow calls from other devices is clicked on, I also see my MacBook Air listed there and it is also clicked on. This makes me think the issue is somewhere in iCloud or the Mac.

The iPhone is running IOS 9.1 and the MacBook Air is running version 10.11.1 El Capitan.

I am am to use regular T-Mobile WiFi calling and also am able to use WiFi continuity to make and receive calls on my MacBook air when my iPhone is on and logged onto the same WiFi network as my MacBook Air.

The only restriction on my T-Mobile line is Content Blocking for messaging, but I removed it yesterday and then tried on the Mac's FaceTime but got the same result when trying calls from other devices, so I don't believe that has anything to do with calls from other devices not working so I have put content blocking back on the line.

I have an active case with Apple Support about this issue and will update the community when I hear something.

Thank you,

Steve