I would be glad to help. What ringtone are you trying to remove? You wouldn't be able to remove a preloaded ringtone. A Ringtone that you downloaded may be under music.
To delete music or videos: 1) Tap Music > Songs or Video and keep tapping until you navigate to the item you want to delete. 2) Tap the item’s title (not the art) to open the item’s detail screen. 3) Tap to delete the item from your phone. You’ll be asked to confirm.
Or if that doesn't work you could reset the device completely.
Tap About Your phone
Tap Erase Phone Data
Tap to erase all your personal data from the phone. This is a drastic measure as it erases all your sign-in information, settings, contacts, favorites, photos, videos, music, and
messages from your phone. You will be asked to confirm.
Please let me know if you have any any further questions that I could help with.