t-mobile internet not working after jailbreak. please help!

hey guys i just jailbreok my unlocked iphone 3g, which is running 2.2.1 version and has t-mobile with turbo sim. after jailbreaking internet worked but when i wake up in the morning, i took my iphone and went to internet but it wasn;t working. i have t-mobile $24.99 data plan. unlimited internet + 400 text message and i was getting E symbol on iphone. i set my apn to internet2.voicestream.com.. pls help how do i get my internet back