Hi @Fedupofmyphone
Welcome to the community!
Sorry to hear you're experiencing issues with your phone changing the format numbers are displayed. This is a known issue on Apple updates and is not a Virgin Mobile issue.
Can you try changing your location to anywhere other than UK on your phone, then reboot phone, once rebooted, change back to UK and reboot phone again, this has helped resolves the issue in some customers. If not, please seek help and advise from Apple support.