I followed the rules in that link https://www.samsung.com/uk/support/mobile-devices/how-to-activate-wifi-calling-on-a-galaxy-smartphone/?srsltid=AfmBOoqurrNu0FEPryf5gfjehJVM47krst9ZoJy5-mxLvccQoM7PyWTpBut WiFi calling switch isn't available in the se...