I once had this problem. I sent in my phone to unlock, but when i get back my phone..the network still shows as active.

However, the shop did ask me to do a few things:
1) Set the network to 3G & 2G (mine is Storm)
2) call ##000000, and set the number to your local number

And then i could call and sms and so on..but it still shows network as active, hence i upgraded the firmware to OS 5.0 and the network shows as Inactive now...no idea why thou.