De register phone number from iMessage and FaceTime that I no longer have
How can I de register a phone number from iMessage and FaceTime I no longer have?
Well the best thing to do right now is contact support, you can click "Contact Support" top right corner of this page and follow the leads until you reach the Phone or Chat options.
They are very busy right now so you may have to try a few times, also some options are not always immediately available, but will become available as demand decreases.
Or maybe try here...Contact Apple for support and service - Apple Support