How do I turn off Wi-Fi calling in build 10512?

I switched back to Android a couple of weeks ago because wifi calling and hotspot were not working. Rarely, the wifi icon would show on the notification bar with the phone, but it wouldn't make calls.

I don't have my phone with me but it was buried somewhere in settings, network, cellular (or module), click on the sim and scroll down from there. Again, without my phone, I'm going from memory but you should be able to find it.