HI ​@Joe Hutson 

Thank you for getting in touch. We’re sorry to hear that you’re currently experiencing issues with your service.

If your SIM is still in your old phone and you are only able to use WiFi calling, it may be related to network coverage, phone settings, or the SIM connection. Please try restarting your phone and ensuring that mobile data and network selection are turned on in your settings.

You can also check the coverage in your area using the following link:
https://www.idmobile.co.uk/help-and-advice/coverage

Additionally, you may want to try the following steps:
Reinsert your SIM or try it in another phone. This will help determine whether the issue is with the handset or the SIM card.

For iPhone (iOS) – Reset Network Settings:
Go to Settings → General.
Tap Transfer or Reset iPhone → Reset → Reset Network Settings.
Confirm the reset when prompted.
Once complete, return to the home screen and restart your iPhone.

For Samsung – Reset Network Settings:
From the Home screen, swipe up to access Apps → Settings → Connections → Mobile Networks → Network Operators.
Turn Select Automatically on or off.
Alternatively:
Go to Settings → General Management → Reset → Reset Network Settings.
Confirm by tapping Reset Settings.

Thank you,

Zandile 

The iD Mobile Team