Cannot activate iMessage/Facetime after change of phone number I had to change my phone number / service provider on my phone (iPhone 5s), and while everything else seems to be working OK, I am unable to activate iMessage or Facetime with my new number.

Whenever I go into Settings > Messages or Facetime I turn them on and it says "Waiting for activation..." then after a while (several minutes) it fails "Activation unsuccessful".  The phone number shown in Messages and Facetime is my old number (now incorrect) - in this screenshot with area code 664

 

The phone number in my phone, Apple account and iCloud etc. is my new (correct) number - in this screenshot with area code 661.

 

I have tried a number of suggestions I've found online: turning off iMessage &amp; Facetime and restarting phone; changing phone number and changing back; signing out of AppleID throughout phone then signing back in - however I still can't activate them.  

Please note that facetime and imessage are working fine using my appleID, and I'm able to send/receive SMS (including SMS from Apple).  

The issue seems to be that Messages/Facetime is trying to activate on the old number but I can't change that number to the new one.

How can I change that activation phone number and activate iMessage and Facetime for my new number?
According to Apple (https://support.apple.com/en-ca/HT201349) you should follow these steps:

"If the phone number that you want to remove belongs to an iPhone that you can't access, change your Apple ID password. This removes all phone numbers from your iPad, iPod touch, and Mac. Calls or messages for the removed numbers won't appear on those devices anymore.?

I would sign out of everything associated with your Apple ID on all of your devices before changing your password (including iTunes Store, App Store, iCloud, Facetime, iMessage, etc).  It saves quite the headache with password prompts popping up and things just not working properly due to things like 'Find My iPhone' being so stubborn. Having a backup of your iPhone probably wouldn't hurt either.

If this does not work I would strongly advise to call Apple. It's been a few years since I've had to troubleshoot this issue but if memory serves me well I believe there is something they actually have to do from their end if a phone number is 'stuck' to an Apple ID.