iPhone 3g is unlocked with black sn0w and is not unlocking with T mobile Sim HELP!!!!

[XUL]

So my friend has a activated T mobile sim with a sidekick plan on it,He told me the steps on how to do it and i did as said
1.made sure iphone was on 3.1.2 with 05.11.07 firmwar
2.jailbroke with blackra1n
3.installed black sn0w from blackra1n
4.then i put my activated t mobile sim inside
and then it just sais no service,i checked the t mobile service map thing and i should have perfect service in my area.And it always sais I have a voicemail,ive restored and jailbroke and unlocked so many times and nothing,its really frustrating.
PLEASE HELP!!!!!!!!!!!I dont know how to downgrade and i dont have a proper bootloader,i also dont know how to jailbreak with quickpwn if anyone knows how to jailbreak with quickpwn with an windows xp computer please help!!!!

[adp]

Try using someone else's SIM card. Does your friend's SIM card work in his phone? It may not be the unlock itself. If another SIM card doesn't work, then it's something related to your phone.

[steve-z17]

Read this, it's pretty easy to Jailbreak/Unlock if you follow the instructions.