Sometimes this can happen for a few hours after a number transfer! I know you posted a few days ago, is this something you are still experiencing?
Also, since you are new to T-Mobile, please don't hesitate to ask any other questions you may have! Welcome to T-Mobile and we're so happy to have you on Support!
Hi, may3inhim !
I just wanted to swing by to see if your services are working now and showing the correct phone number. As Lauren mentioned, there may be a brief period during the transfer of services that will cause this to happen.
Howdy, may3inhim! Just wanted to make sure the system worked this out on its own over time. Please let us know if you're still having issues, especially if you're using an iOS device and if the question is regarding the number you see listed as yours on your iPhone! We're happy to help if needed.