I have had my Sprint LG Optimus S since November. I use Handcent and the stock dialer/contact app. Lately my phone has been changing ringtones to "unknown" ringtones and making horrible noises. Also, some contacts ringtones won't change. It says they are changed but it still plays the wrong song when I receive a call (doesn't happen with all contacts). Why does this happen and how I can fix it? Messaging ringtones all work perfectly.