Music app in iPhone 6 deletes music artwork and songs

Question

I have spent hours trying to fix this, but have had to restore factory settings and replace 10,000+ songs to the phone twice now. I use a MacBook Pro with iTunes 12..0.1.26. I bought the 128GB iPhone 6 for the purpose of playing my large CD collection. What happens is that after adding music to my phone, I can listen to it without problems for a few weeks, and then suddenly one day all of the artwork will disappear, and when I try to play songs in a playlist it will flash up the name of each song one by one and then give a message that there are no songs to play. When I check the music library the songs are no longer on the phone. This happens with all songs except ones purchased from the iTunes Store.
I have set iTunes to manage music manually and unchecked all sync options. I have disabled iTunes Store and iTunes Match on the phone. I have "hidden" iTunes Radio on the phone. "Show All Music" and "Genius" are both disabled in the settings for the music app. I have turned cellular data off for the music app. I have even tried to trick Autofill by creating an empty folder to Autofill from as there is no option to turn Autofill off. I guess my problem is that I have spent a lot of money on CD's and Apple wants me to buy all of my music from iTunes. It would be cheaper to buy a new (non-Apple) phone than to buy my music twice, but I would prefer to stick with my iPhone if I can find a solution.

Answer 1

I have worked it out. All you have to do is sync the music from iTunes. It is not possible to delete music from the computer while keeping it on the iPhone. Then, whenever you want to add a few new songs, delete the entire phone, restore factory settings and start again. It only takes a couple of hours each time. Well done Apple - what an intuitive system.