I can certainly understand your disappointment with the Wi-Fi Calling feature not working on your newly purchased Google Pixel 3's. =(
I really wish I had better news but unfortunately, at this time, only Android devices purchased from Rogers can use Wi-Fi calling on the Rogers Network.
If this changes at any time we will keep the Community updated.
Anyone knows if other carriers like bell and Telus also block phones purchased through Google? I am seriously considering changing providers.
For what it is worth, tried to set up wifi calling on the Pixel 3 purchased from Google with a bell SIM, did not even get the option to activate wifi calling. Tried it on the Pixel 2 XL that was purchased from Rogers, no luck either. It is a shame we do not have a lot of providers in Canada and we are stuck with terrible expensive service.