I had an issue with people trying to send iMessages to my phone number.
for some reason ios7 had set iMessages to only send to my email address and not to my phone number.
to fix it, I had to get the help from my boss at work :)
its an easy fix:
go to settings > messages
scroll down to ‘send & receive’
go in to ‘send & recieve’
click on the ‘apple ID: firstname.lastname@example.org’
click sign out
your phone will now be set to only send / receive from your phone number.
click on ‘Use your apple ID for iMessage’
once signed in , click ‘next’ (its up at the top of the screen)
your phone will ‘verify’
and then it will show you the list of your email addresses AND your phone number
[ it will also pop up messages on your other devices telling you that your number was added to your iMessage ]