G1 is not Activating

[Major Lazy]

Hello- just got my G1 yesterday as a b-day gift. Called T-mobile to upgrade my service and slipped in my SIM card from my old phone as instructed. T-mobile said it would be 2-4 hours before I could use my phone. 12 hours later I'm still getting the error message, NO SIM CARD, EMERGENCY CALLS ONLY. So I need to take it to a T-Mobile store to activate??

Any help is appreciated!