Happy to help but please can you explain a little further.
Are you moving your number to us from another network? Have you received a replacement sim card and are looking for your old number to be moved across? Have you tried switching the phone off and on again? If you've received a replacement sim card from us and you wish to have your old number on it then you'll need to activate the new sim card first.
You can activate the new sim card using this link https://www.o2.co.uk/help/device-and-sim-support/activating-your-sim.
The only way to get your number written to your sim is to put your sim in an iPhone and go to Settings >Phone >My Number where you can enter your number and save it.
This will then be written to the sim and will be transferrable to another phone.
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