iTunes
i just switched back to Apple the music purchased is not on the phone how do i get it back on there?
iPhone 6s Plus, iOS 9.3.5
If it's still in the store, and if you haven't moved countries since buying it, then it should show in the Purchased tab in the iTunes Store app for redownloading
If not all music shows there check to see if you've hidden it from the cloud : Hide and unhide iTunes Store, App Store, or iBooks Store purchases - Apple Support