O2 don't do consumer landlines anymore and a full breakdown of charges are in your MyO2 http://www.o2.co.uk/myo2
Otherwise, call customer services.
Numbers to try here Guide: Coronavirus Community Help and Support
Please read reply above.
If you need call costs they are also in your MyO2.
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 Do not publish personal details (email, phone number, bank account).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
As above @Fenton14
All numbers on this guide Guide: Coronavirus Community Help and Support