Just checking the obvious (I assume you have this right):
1. Your phone is iPhone. And on iPhone your phone number is listed in "can reach at".
2. You have your own contact card in Contacts, filled with that phone number, and in Preference, in Users & Groups you have that card set in your profile?
3. And you have the phone number in the AppleID configuration? Check on https://appleid.apple.com/
May be call Apple support? Seems interesting challenge.
You can try editing your AppleID account - https://appleid.apple.com/account/manage
Your iPhone number should be listed in "Reachable at"
If not, you can add your phone number there.
You may need to sign out of both Facetime and iMessage on your iPhone. Change your phone number as you want it, then sign back in to iMessage and Facetime.
That should do it.
If not, follow Honza1 tip to call Apple support.