I had an LG G7 with an O2 contract for a number of years and then got a new phone from O2 very recently that I moved to. Now I'd like my wife to use my old phone. She's not on O2 and when I moved her SIM to my old phone there is apparently no network signal at all. Move the SIM back to her phone and it works fine. Not finding any way to speak to a human at O2, a bit of research and I read about phone unlocking and found how to request that on O2. I supplied the IMEI number and then a couple of days later got an email that provided me with a procedure to get to a special menu with the option 'Service Provider Lock' which they said I could use to unlock the handset. But when I try this procedure the message says 'Your phone is not personalised'. Of course I couldn't reply to the email because it bounces back with "Thanks for your email, but we have now shut down our email support service"!
Can someone suggest what might be going wrong and who I should attempt to speak to next?
I would get a replacement sim card for your wifes phone as the first port of call and trying that.
I would normally suggest speaking to LG after that but they no longer exist in the Mobile Phone Market, but you an still try and get support on the phone here Get Product Help & Support | LG U.K. Support
The LG G7 has always been a problem to unlock and it's not always successful.
Within the service menu there is also a network lock option so you could try to enter your code there but if not, it may not be possible unless you try a local phone repair shop with the correct software.