New phone won’t transfer number across properly

[AnnaFC]

I was told to change number in settings 

and in Apple ID but it won’t allow me to the phone seems to now be locked to the number that came on the sim (was an existing o2 number sim only account on a tablet) that came with new phone and I can only delete the number transferred over from sky which is the one I want to keep 

that number is now bouncing back on people argh 

I’m not getting codes through to set stuff up or calls/texts work and personal . Need help with this asap if anyone has been through this

[MI5]

@AnnaFC 

Have you tried resetting your network settings first?

If so, you will need a new sim. Pop into any O2 store with photo ID for a new blank sim.