Have you rebooted your phone?
It may not be on over the weekend. Keep rebooting the phone. You could call O2. All numbers in this guide Guide: Coronavirus Community Help and Support
Advice from an O2 Guru regarding a way to get through:
If you call 202, when it comes to the reason you are calling, stay silent for 15 seconds and you will be taken to the keypad options.
Press 2 for Everything Else
Press 5 for More Options
Press 7 for Anything Else which will put you though to someone.
Also, press Fraud or Lost and Stolen if given that option.
*The Game Is On*
If rebooting does't help I'll ask @O2Daniel to see if he cam help.
Track usage, upgrade and get support with the My O2 appDownload My O2