O2

I have put my SIM into a new phone, because the one I was using dided yesterday.The new device is asking for a SIM metwork unlock PIN, but I don't remember it. Nor I have it written down anywhere. Can I activate my SIM through my O2 app? If so, would...

I want to change my billing date and I have been on the O2 website for an hour now, jumping between the same five pages over and over again!The website will not direct me to the contacts page, no matter how hard I have tried!Can someone point me in t...