Oh boy magenta2337592 . That's a bummer this change didn't happen how you wanted but there may be a way to help you out. Since this is an account change, you should Contact Us and reach out to our social support team. They can take a look at your account and see what happened with switch. They may also be able to clear up what the reason why your number didn't change over.
Call into T-mobile support and work with a rep. I'm sure they can help you get this resolved.