For many years now, I have been unable to port an existing phone number into any of my TMO phones because "it was already a tmobile number". I had ported it from Sprint in an attempt to keep the phone number, so, it became a prepaid phone.
Over the past weekend, I added two more lines to my tmo family plan, and now have five lines on my family plan, with the 'kids are free until 2010' program. Which lowered the monthly bill by $9.99. So, I got to thinking, and decided that the fifth line, which isn't being used by anyone, should be the one to adopt the number from the prepaid phone.
So I called tmo, and to my surprise, had absolutely no issue with the rep. I'd used the prepaid earlier in the day to donate parts of the prepaid balance to charity, so I'd already used up most of the prepaid balance. After talking with the first rep, she sent me over to 'prepaid' to cancel the phone number. Of course, prepaid had absolutely no idea, so they forwarded me to 'activations'. Activations was also clueless, and, after a while, while they were trying to do whatever the first rep did, they advised that the change was complete. So I thanked her, and hung up.
I then went to look for the phone - it was still unopened. Broke out the sim, plugged it into an AT&T unlocked phone, and dialed #NUM# and presto - the number was there.
Yeah!
(after all these years)