Manually added songs keep appearing in iTunes when I sync

When I sync with iTunes music shows in the 'Manually Added' window. The music in this window totals about a hundred songs; a couple of songs each from various albums. I think it may be purchased music, or recently played music. I un-tick all playlists and delete the music in the 'manually added window and apply; then I delete the music on my iPhone 5 with iOS 10 by going into usage; I have also in the past manually deleted every album that appears on the iPhone. But when I reconnect the phone to iTunes the 'Manually Added' songs return, and phantom unplayable song details appear in my iPhone. This happens time and again. It is a 'brand new' iPhone 5 sent from Apple, and I have erased all settings and content several times. But the music keeps appearing. I do not have Apple Music. I do not share my music in the cloud (I used Apple Music once but it was awful so I stopped). ** this used to happen before Apple Music existed anyway. I have spent dozens of hours searching for a solution online. Please help