Ellie says that Apple Music has screwed up her phone. Leo says that the problem lies with having iTunes Match. What that means is that her phone isn't setup with iCloud Drive, so her phone just doesn't see the files. It hasn't been deleted, it's still in the cloud. iCloud Music Library and Apple Music must be turned on. Otherwise, it will only see the puchased content.
So Ellie should enable iCloud drive and she should see all of her music. Leo says that Apple has done a terrible job educating people as to how Apple Music works with iTunes Match. Check out this experience by Jim Dalrymple at loopinsight.com.