They're looking for beta testers!
https://www.t-mobile.com/coverage/satellite-phone-service?sdtid=17997126
The T-Mobile Starlink beta enables us to test the service in real world circumstances to ensure it meets our high standards before launch. Customers who register will get a chance to be one of the first to experience direct-to-cell satellite service. We expect the beta to begin in early 2025, starting with texting and expanding to data and voice over time. The beta is open to all T-Mobile postpaid customers for free, but capacity is limited. Customers are encouraged to register now.