Apple Deleted My Music

I use Music (previously iTunes) on my Mac and link that library to my iPhone. My library contains music purchased from Apple, music purchased from Amazon, and music uploaded from compact discs that I purchased with real money.

I recently found that all non-Apple music had been deleted from my library without my knowledge or consent. This vandalization occurred before my oldest backup.

I've tried to discuss this matter with Apple support, and they've twice escalated to a telephone consultation, but they NEVER actually make the call.

What's a better music player (not streamer) app for Mac and iPhone?