I have searched for this and couldn't find a thread dealing with the same exact issue. I like the app and it works great except for one contact. Everyone works but one contact doesn't show up at all in Handcent and when he sends me a message it will sometimes pop up but wont play a sound. And most times the phone will just come out of sleep, but not pop up the message. Like I said it is only with one contact. It's driving me crazy.