S2 no network/ network or sim error

[Trudi Wiseman]

Having received the mobile from the insurance company. I inserted the sim card and it would not acknowledge it. I have no signal and thus cant use the phone as a phone.! Have tried putting in all the settings for o2 manually but nothing works. It has been sent back to the company once and they assured me it was working. The sim works in other phones no problem. The phone is locked to o2 and after checking is not blackllisted. Can anyone help. Please....