Wifi calling not working

[Dave52]

Wifi calling not working on both Samsung Galaxy S10 Plus & Apple iPhone 13 Pro Max even though 4G / WiFi enabled in both O2 accounts

[Dave52]

And yes I've gone through all O2's advice

[pgn]

So you have contacted O2 and asked them to turn WiFi Calling on in your account (as it's not enabled by default)? This then lets you select it in the phone settings.

O2 are contactable on 202 (08:10am UK time is less busy) or via Social media, links to which are in the page linked just below this post. O2 state now that all phones sold by O2 support the feature, so long as they are on a Contract or Business tariff, @Dave52.