Getting 4F VoTLE working on my Samsung S10+ Phone?

Hi All,

I have a Samsung S10+ phone which, according to the Specification Sheet, should enable 4G calls (4G VoLTE) to be enabled on my phone. I'm running Android version 12 (also a requirement).

Yet the 4G VoLTE option doesn't appear under the Mobile Network settings?

Instead it shows 'LTE/3G/2G' as the only option.

Does anyone have experience of how to solve this issue please? I've just joined Smarty, which required a new SIM, so it's not that! I have been unable to find any cause for this issue so far...

Many Thanks!!!

Susanna