Share your experience!
Ok,settings-apps-all-media storage,force stop and clear data.Restart.
Have you connected your phone to a Pc to try and which files are they
Or have you tried to use file commander?
So you have removed them and they are still there? Can they still be played?
So they are just ghost files.
Clear data on Walkman app and restart your phone.
Try it.
You are welcome.