I see a lot of similar topics.
New ID mobile SIM in s7 edge (previously with Vodafone and phone unlocked). WIFI calling always worked with Vodafone, required as coverage in house poor.
Many, many conversations with id support service who cannot sort (they say enabled) - also apparently getting a call back from tech support within 2-3 days with solution (promised before).
Aware may be firmware issue, so phone has been flashed to BTU open source firmware and latest available update (Oreo). SIM from Vodafone activates WIFI calling, but with Id sim, no option to do same.
Any ideas from anyone? Not all impressed with ID support.