I've moved from Virgin to O2 in the last few days. I supplied a PAC to O2 during the switching process and received my new O2 SIM. I inserted both SIMs to my mobile in the evening and O2 confirmed that the port would happen in two days time (since the process had been triggered after hours, as expected). That day was yesterday and around noon both SIMs became "unregistered with network" and stopped working. Previously, the both SIMs were functioning - the O2 one with number the SIM was shipped with and the Virgin one with my long term number. My partner called my phone and my old ported number was now going to the O2 voicemail service. My ported number was now also showing in my O2 account.
It now been over 24 hours since service was lost. I have restarted the phone many, many times, did a network reset too but the SIM is still showing as not registered with network, cannot use data, text, make or receive calls. Incoming calls just go straight to O2 voicemail.
Any further device suggestions, or is this likely to be an account issue?
Sounds like a faulty SIM.
Pop into your local o2 store to swap to a new one.