The normal process is not working for me.
Is this similar to what you did? Specifically, did you log out of your AppleID anywhere ...
* I logged out of my AppleID in iMessage, FaceTime, iCloud and iTunes & App store.
* Then turned off iMessage and FaceTime, and then restarted phone.
* After phone restarted (and signed of iTunes & App store again), I turned on iMessage.
Since then, the iMessage is showing "Waiting for activation". Now over 2 hours ago.
But I could not get the manual method to work after trying over 20 times over the past day - the Hex string was never sent.
I'm not sure why neither route is working now.