removing media files from device that have been sync previously but not showing up in new updated ap

I have some media files that have been previously synced to an IPad and now with the new updates to the apps and everything when I go to the sync area in the app to remove the media it says there are no files there but if you turn on “offline mode” and browse the local device they are most certainly there. How do I remove them? I tried removing the entire app and re-installing and they are still showing up. Please help.