Removal of purchased music on Apple Music

Good day,

I have a question about purchased music on Apple Music:

What happens when an album that you have purchased and downloaded gets removed from Apple Music?

I am thinking of buying "Love trip" by Takako Mamiya, as her entire discography has been removed from Spotify, but I am afraid that the same thing might happen to Apple Music.

Does one get a refund? Or will the songs just be unavailable until the music rights (hopefully) get renewed? And will I have to purchase it all again?

Thanks in advance!

(I use a MacBook Air from late 2014 and an iPhone 7)