Keep in Touch Using Wi-Fi Calling

I have a Samsung Galaxy S7 edge updated to Android version 8.0.0 but WIFI calling does not appear anywhere in the settings menu.

Who is responsible for determinig why this is happening, ID Mobile or Samsung.

I had similar experiences with a Samsung S7 phone and as far as I could work out the absence of the Wi-Fi calling option on the ID network was due to the phone originally being locked to the EE network and even though it was subsequently unlocked Wi-Fi calling was never possible.  The same SIM in a compatible iPhone worked fine for Wi-Fi calling so neither the ID network or the SIM were the problem. Puzzlingly, in a later Samsing S7 Edge however, also previously on EE, the SIM worked fine so my only conclusion was that the older S7 from EE was the issue.  I tested the theory with my local Mobile shop who helpfully pulled out some other unlocked S7s off EE and they also would not offer Wi-Fi calling on the menu whilst hosting the ID SIM 🤔.  Solution: buy a later Samsung model?