Now I thought someone came here a few weeks back to say that an update had made the Darkballs respawn? What I'm saying is, there might be a deeper problem here that will need you to talk to tech support... or possibly there's none at all. Did you know that when you click on an enemy to fight it, the combat is completed on the server-side instantaneously? The animations are just for show: the game has already recorded whether or not you won or lost, and if you lost, all it's waiting for is to see if you click Continue or not, at which point it simulates the next round. This way it almost never loses data to accidents like this.
My point is, unless you knew you were going to lose, what probably happened is that you won, the Darkball is dead and the game is just waiting for you to find the last one - or you did kill the last one, the game advanced the plot while you were offline, and is now waiting for you to talk to Chirithy, but maybe you already tried that. My advice is to follow nuyi's advice, because that's an easy Darkball to miss.
