How can delete songs from iPhone permanently

The music that I have on my iPhone is taken from 5 playlists on iTunes, one of which has all of the music that I listen to on it. I have 4 songs that I don't like any more that I have been trying to delete, but every time I sync, they redownload. I have checked and none of them are in any of the 5 playlists. even when I manually delete them from the music app, they try to download again when I sync. In iTunes, my iPhone is set to sync only those playlists and nothing else. My phone is running the most recent update of iOS 6.