hi. i'm using an iphone 4 on 7.1.2, newly restored and activated. imessage and facetime are both activated but only facetime works as it should. when i try to send a imessage to my 4s or ipad (all 3 connected to home wifi) the receiver text turns blue and the headline changes from "New Message" to "New iMessage" and the text box has a grey coloured "iMessage". but when i start typing my message the receiver text turns green and when i press send i get "XXXX is Unavailable This person cannot be reached by iMessage at this time." but when i use imessage to send texts between my 4s and ipad everything works fine, its only my iphone 4 that can't use imessage. when i text my iphone 4 from my 4s or ipad it gets delivered as an imessage but my iphone 4 never receives it.