When I go to My O2 Account, and look at "My Devices" it tells me what king of iPhone I have, and the IMEI number. The trouble is, both are wrong, compared with what I see on my phone, when I go to Settings. Why might they be different, and does it matter?
You'll need to call O2.
Numbers here Guide: Coronavirus Community Help and Support
Advice from an O2 Guru regarding a way to get through:
If you call 202, when it comes to the reason you are calling stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to an advisor.
Press Upgrade, Lost/Stolen or Fraud if you have to.
*The Game Is On*
Device updayes are supposed to be automatic, but occasionally they can take a while.
In reality, for your case, it makes no difference whatsoever.