Unlocked 7250i but still not working!!! HELP

I have managed to unlock my Nokia 7250i from Orange and have tried using 2 different T-Mobile PAYG sim cards, neither of which seem to work, you can see the T-Mobile logo and the network strength is good but when i try to call i just get a series of beebs . . i know both sim cards work cause have tried them in several different phones.... whats wrong . . . please HELP!!!

the beeps mean it is network "blocked" as it has been reported lost/stolen....nothing you can do about it unless you bought it second hand and can get your money back..