I can help you

Here is why it thinks it's blocked..

Did you have to jailbreak the device to run on vodaphone????

If so you might have a large issue.

Iphone os update 5.0.1 currently has some new features that if hacked or unlocked by a jailbreak or network unlock will deam the iPhone unable to use it's cell phone sim card.

Models affected:

Iphone 3gs

iphone 4

iphone 4s

So far from what we understand about it the new o.s is sending some sort of data package that the cell towers don't recognize and then lockout out the phone by denying access to the sim card.

you can tell if you are having this issue by these symptoms.

1. your iPhone says no signal activation required

2. your iPhone goes into internal loop mode where it goes to the lock screen and returns to the apple loading screen for the iPhone os.

this is very common right now the only thing i can tell you is keep the phone on i.o.s 5.0 because the 5.0.1 jailbreaks all seem to be tripping this feature which doesn't help anyone.