@Malted
where you got the phone from? from which carrier?
If the message is "SIM network unlock PIN" or "SIM ME lock code NP" or "SIM not Supported" or on an iPhone's About->Carrier Lock showing "SIM locked"
You have to ask the carrier where you got the phone from for the carrier help unlocking it.
(Sorry, for this particular issue, PM support would not be able to help)
