What should I do if my Music Library disappeared on Mac?

For years I have been paying for ITunes and Apple Music. My music library completely disappeared from my MAC. Over the years I called Apple support to restore it and it never gets completed. I basically gave up. But I am truly upset that somehow Apple was able to erase my music collection on my PC. I kept renewing my ITunes in hope O can somehow get it back. Life gets in the way and it is really upsetting to spend hours on the phone with Apple Support and never get it restored.

[Re-Titled by Moderator]