The SurvivalGames plugin tries to reduce the ability for PvP logging to be effective. If you hit another player and they disconnect, they still lose the points that they normally would. The only time when a player can disconnect and not lose points is when they have not been hit and the death counts as an elimination rather than a kill.
Therefore, if you hit him before he disconnected, you should have received the appropriate bounty.
I consider this topic answered, and therefore will proceed to lock it. If you have any further comments, questions or issues, please feel free to contact me or another staff member directly.