Cleaning apps such as "Phone Master" have been known to delete Audiomack music downloads. If you have Phone Master on your phone you can fix this issue by disabling the app or shutting off Smart Cleanup. We will go through both options in this article.
Disable Phone Master:
First, long press the Phone Master app and click 'Application details'

Next, Click 'DISABLE'

Next, click 'DISABLE APP'

If the above instructions do not work, open the Phone Master app and click 'Smart Cleanup'

Next, click the blue button to shut off 'Scheduled Cleanup'

Next, click 'DISABLE'

IMPORTANT: IF NEITHER OPTION WORKS FOR YOU, PLEASE GO TO SETTINGS AND DISABLE PHONE MASTER'S ABILITY TO ACCESS STORAGE.