It seems that when you first activate your iphone the number is stored on the facetime server, then each time you attempt to make a facetime call it checks the server for that number (even if you activate facetime directly from the contact list it sends a SMS in the background to check). So, when your number changes to the ported number facetime thinks its called a non iphone 4 number.
Do not despair, a solution is here and its worked for me and a few others. Goto Settings General Reset Reset all settings.
This will reset all your preferences and settings, data such as your contacts list and media such as your songs and videos are not deleted.
Do not despair, a solution is here and its worked for me and a few others. Goto Settings General Reset Reset all settings.
This will reset all your preferences and settings, data such as your contacts list and media such as your songs and videos are not deleted.