New iPhone X

[Zuhoor]

I feel like i’m being silly and missed something, I’ve just upgraded to an iphone X keeping the same simcard. I’ve put my sim into my new phone and it says no service. Is there something else I forgot to do?

[MI5]

Sounds like they may have transferred you to the new sim.
Have you tried that?
If not, the old sim should still be working.

[Cleoriff]

@ZuhoorIf you have rebooted your phone a few times and are still getting No Service, you need to ring customer services, if you want to keep your existing number.

https://www.o2.co.uk/help/phones-sims-and-devices/how-to-keep-your-mobile-number

If they have already activated your new sim (which is strange) then you will need to do a sim swap.

http://swapmysim.o2.co.uk/

It's far quicker to call O2 between 8-8.30 am this morning. Or even pop instore and explain the problem to them.

They will handle it far more quickly than you attempting to do it yourself.

Best of luck and welcome to the forum 

[EmilieT]

Hi @Zuhoor, I hope the info above helps you get this working, but please keep us in the loop of your progress