Music disappeared from Apple Music with error "Unavailable in your country or region"

I’ve been dealing with this some extent or another for years. Music that I PAID FOR on iTunes has magically disappeared!

I had to replace a broken phone and today half of my music is “unavailable in your country or region”

This is music I paid for! I own it! I want it back!

[Re-Titled by Moderator]

Original Title: Apple has stolen my music