My country code isn’t registered for deregistering my phone number
My country code (Jordan +962) isn’t registered for deregistering my phone number online
Question marked as
What about on the phone itself?
Deregister iMessage on your iPhone or online - Apple Support
If you still have problems:
Click here --> https://support.apple.com/choose-country-region Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.
or:
Contact Apple for support and service --> "See a list of Apple phone numbers around the world."
Click here --> https://support.apple.com/HT201232