Sidekick 3 Registration

I have bought a Unlocked Sidekick 3 off e-bay. When i put my T-mobile
sim card in it, i am presented with a registration screen that advises
me to wait upto 48hrs for the registration...

72hrs later, still at the same screen.

I have spoke with t-mob & they have advised the Sidekick service is
active on my account.

Does anyone have any ideas what i can do???

Thanx in advance