I was looking through threds and I think I may have found a solution thanks to firey05
I have been having the same problem since activating and have tried all the steps provided by everyone
- Reset Network Settings
- Erase All Content and Settings
- Restore from backup
- etc etc etc
I was at the shopping centre today and popped into the Apple Store
I was informed the following;
"We are aware that there have been some issues with iMessage activation. Those on Optus and Vodafone are ok, it is mainly affecting those on Telstra"
Apple also advised that if iMessage activates with your apple ID and not your phone number then this means that the APPLE SERVERS ARE WORKING FINE.
The phone number is ONLY activated through your carrier and due to the demand it's SLOW
Just wait it out, try an obsure time of day to activate like 3AM when most are sleeping
DON'T BOTHER restoring, resetting etc etc.