What's the sitch on Amazon prime music Unlisted Video

According to Business Insider, "The Amazon Prime membership comes with access to Prime Music, a catalog of more than two million songs and thousands of curated playlists." It should also be known $7.99 per month will upgrade users to Amazon Music Unlimited and it will unlock tens of millions more songs. For anyone looking to join, it should be known that songs are occasionally removed and added to Amazon's selection.