FaceTime App missing in Cellular Data

If your carrier supports it you can turn FaceTime On in

Settings > Mobile/Cellular > section MOBILE/CELLULAR DATA > FaceTime: ON here.

This response is not helpful. I have this issue on my wife’s phone. We are on the same carrier/account. On my phone FaceTime works on LTE and shows up in settings>cellular. I note, however, as stated in this post, that the option for FaceTime is simply not available under settings>cellular data ... it just doesn’t show up. FaceTime is turned on. I’ve reset FaceTime and messaging and both work fine on WiFi. Messaging works fine on LTE. It will not work on LTE. I have gone though all the cellular settings on both phones side by side and this is the only difference I can find. I can’t turn it on because it doesn’t show up.

Not helpful. Will you please answer the question?