So I always buy my iPhones from the Apple store. My new 6S works fine - but unfortunately the signal in my area is patchy and sometime I cant get signal (thanks Vodafone!) - so wi-fi calling would be a really useful feature. I called Vodafone to ask them to activate the wi-fi calling feature on my account (the phone wont enable it via the setting menu - asks you to call your carrier) - and after the usual pass around and long hold with Vodafone - I eventually got hold of someone - who basically told me that despite me having a £40 per month "Red" bundle - they wouldn't activate the wi-fi calling feature as I didn't buy the phone from Vodafone!!! ...and my only option would be to take out a new 24 month contract with phone from them! Errr....no thanks!! I did point out to them that the reason I wanted wi-fi calling was that their signal was poor....but as you'd expect that was met with the usual Vodafone indifference! So anyone thinking of buying a phone at the Apple store - consider using EE as your carrier as I think they give w-fi calling to all their bundled customers.