How to stop using iCloud Music Library on Mac and iOS?

I had the same problem. I searched and found a few articles and threads that dealt with similar issues. It looks like the option to turn off iCloud Music Library for both the iPhone and Mac has been hidden in iTunes >> Preferences >> General. Uncheck the box next to "Show Apple Music". After unchecking the box you are given a message about iCloud Music Library. Next, you will want to reset your iCloud Music Library settings in iTunes. Go to Store >> View Account, enter your Apple ID and Password, then click "View Account". Once the Account Information page loads, scroll to the bottom and click the "Reset" button for the option to reset iCloud Music Library. You will be asked to delete all of the music and libraries stored in iCloud Music Library. Check "I Understand", and click "Reset". After you confirm and click "Reset Now", quit iTunes. Links to the full articles:

• https://support.apple.com/kb/HT204964
• How to prevent iTunes 12.2 from automatically uploading sound tracks to iCloud Music Library?

Now, verify that the settings are correct on your iPhone. Go to Settings >> Music. Under Apple Music, slide OFF "Show Apple Music". Finally, Power off your iPhone for 30 seconds and then power back on. If the music library on your iPhone still contains music from iCloud, tap the Music app, tap Library at the top, tap the red text (will read either: Artists, Albums, Songs, Music Videos, Genres, Composers, or Compilations), then slide ON "Only Offline Music".

Following these steps should provide the results you are trying to obtain. It deletes any music and libraries from iCloud but leaves your original library in tact, allowing you to continue syncing selected playlist, albums, and artists to your iOS devices.