FaceTime Facility Available on iPad But Not On iPhone

When I initiate a Facetime call on my iPad the page that comes up shows:

HOWEVER<

When I do the same on my iPhone the video and phone prompts do not appear:

The contact details on both devices are EXACTLY the same so I don't understand why I can't therefore make a FaceTime call to the intended contact from my iPhone.

Any explanation would be much appreciated please.

[Edited by Moderator]