Unfortunately, we have not been able to get ringtones to work on the Instinct HD to work recently.
It appears that either Sprint or Samsung has blocked the ability to download 3rd party ringtones to this phone.
Sorry about that. We are continuing to look into the problem, but let us know if you have been able to download ringtones from any other site.
The good news is that wallpapers and video should work. We also have full length MP3s available for your computer.