@Help11
This is because wifi calling is enabled.
You need to ask customer service to disable it so you can change your ringtime then you can get wifi calling enabled again if you wish.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion.
This is not Customer Service so we are unable to help with account specific issues.Currently using:
Pixel 7a (O2 & Lyca), One Plus 6 (Sfr), iPhone 12 Pro Max (Vodafone)