I have a P30 Pro and P20 Pro, both on o2 pay monthly. The P30 Pro has a wifi calling option with no problem, however the P20 Pro doesn't show this option in the settings menu.
I have checked on the web portal and it shows wifi calling is enabled, so everything should be set up properly. Any way I can force a refresh/update of my settings to show the wifi calling option?
Can only assume it's not yet active on your account then @Mosmordor
May need to give it a bit longer, but keep rebooting to check.