My partner also had this problem. We both upgraded the same day. I had wifi calling option and he didn't. The only difference was he had a black phone and I had rose gold. We then spent a very stressful month with Vodafone. Visiting stores in Newbury and Bournemouth (whilst on holiday!). We started on chat and they could not resolve it and referred him to the store. They tried a new handset, still no joy. If we swapped sims, then it would work. My partner's sim worked ok in my phone and my sim worked ok in his phone. It seemd that his sim was just not compatible with his phone! The flashed software on to the phone. We tried the "CALLING" to the text number. They checked the APN's. They told us to wait for the next software update. The phone even went to the workshop for a repair! After a few weeks of this runaround we felt the service we were getting was not good enough. My partner bought this phone for this feature as he has dead spots in his house and calls drop. We escalated our problem and emailed the CEO of Vodafone. This is then classed as a complaint. They then get the technical team involved. They tried several things over a week which did not resolve matters. They called him and said they were at the end of the road as to what they could do. The last resort was remove his number from the network, which involved cutting him off for an hour or so and re-adding him. So completely setting him up as a new user on the network. Hey presto, this worked - fantastic! It was come to the conclusion that because my partner was a long standing customer of Vodafone, he had an old account and there were glitches and ghosts on his account. This may also be the reason when two years ago he could not use his phone to dial UK from Spain ........ that's another story. I hope that this helps someone.
