January 20, 2020 1:54 EST PM
AppleCare provides perpetual phone support or chat support for their iCloud services. I don't know which article you followed and all the steps but if you call AppleCare and identify to them which Apple support article you followed for the issue being experienced they will have to provide support and an eventual resolution.
The article you references is from Aug 2018
To use iMessage or FaceTime, you need to activate them on your iPhone, iPad, or iPod touch. If you see an error message during activation then try, If you get an error when trying to activate iMessage or FaceTime
If you can't sign in to iMessage or FaceTime on your Mac, see If you can't sign in to your iMessage account or FaceTime on your Mac.
Note: (Just incase) FaceTime is not available in all countries or regions.
Hope these help.