support.apple.com

Sure, but I was asking about a phone number where I can call and talk to a human who may have more experience in these matters.

The first thing support.apple.com asks me to do (when I want to post a question) is to ask me to log in with my AppleId. My problem is that the AppleId that has always worked in the past no longer seems to work and when I try to create a new one, it says my mobile phone number is invalid.