hI, I recently restore my iphone 4s to factory setting using itunes and my IOS was updated to 6.0, now my sim card cant receive network anymore(no service) i have been told that i need to jailbrk the iphone but b4 that i must downgrade because there is no jailbrk for IOS 6.0, plz can somebody help because im totally stuck for the past 3days cant make or receive calls. thanks in advance