Does your phone show that it is connected to the network @Johnathan12 ?
If not you might have a faulty phone or sim.
Try using your sim in another phone and/or use another sim in your phone - that will let you work out where the fault is.
If you can't do that, request a new sim by calling customer services (or going to your local store) - you can use Skype to call the 0800 number in the guide below:
Guide: Coronavirus Community Help and Support
Please note, this is not customer services and we cannot access your account. Do not publish personal details (email, phone number, bank account).
Link to our guide on how to contact them can be found here
