I have just opened my new phone today (Model SM-G781B/DS). However, the WI-FI calling feature is not working. My Service provider does provide this function. I know this function works perfectly in my other more expensive S20 device . However, transferring the same SIM card into the cheaper S20 FE device reveals that the Wi-Fi calling functions does not work! All android updates on the S20FE have been done, and the phone re-started. I note that the S20FE does have a WI-FI calling app pre-loaded on the phone - I have checked this and is currently activated, but still no indication of WI-FI calling. If this was working then a small logo appears (see image below) Does anyone have any ideas please?