I have an iphone 3gs jailbroken with spirit and unlockd with ultrasn0w ..

Well... apparently i already type in the settings in the Cellular Network but i dont know somehow that the settings been reset..

its like the all the APN i already typed in before is empty like theres nothing been typed there... thus i have to re-type again to make internet works..

but it was there for several hours.. i dont know on what duration will the APN name is reset... anybody have this problem? i really want to know ways to solve this.. thanks!