Already Factory Unlocked iPhone 4 is locked again

[Anonymous]

HI..

My already factory unlocked iPhone 4 unlocked by O2 has been locked again after doing 'erase all content and settings'. I have synced with itunes as well but it says unsupported sim. Kindly help as I am not in UK.

[MI5]

If it was factory unlocked why did you have to get O2 to unlock it? Where did the phone come from originally?

[Anonymous]

it came from O2. i was on pay monthly but my contract ended. 

[MI5]

Most unlikely it was factory unlocked then to start with. If you followed the correct unlock procedure it shouldn't relock as the IMEI will now be registered as an unlocked phone. What have you done recently to the phone?

[Anonymous]

It was unlocked as I was already using other networks sim in it... I have used the reset setting 'erase content and settings' and afterwards itunes says you are using unsupported sim

[MI5]

Have you tried restoring from your last backup?

[Anonymous]

did you get it from carphone warehouse as their phones are unlocked but what they dont tell you & it is in the small print that whichever sim you put in, the phone then locks to that particular network

[Anonymous]

Yes I have but still not working.

[Anonymous]

No i didn't get it from carphone. i got it from O2.

[Anonymous]

did they say it was actually unlocked as if it is from o2 directly, i would imagine it would be locked to o2 anyway