I would suggest in the future if someone wants to play sets for 100(or 50, or 1000, etc) you establish a minimum amount to lock up, and a minimum time period. Say 500 and 6 hours for example. So you guys have to play until someone loses 500 or you've played 6 hours. When one of these two things happen, either of you has the option to quit. Winner or loser, doesn't matter. Make sure they post, or at least show you they have the set amount of money.
Makes things much easier than to just start playing, then they either don't have the money, or you get tired and look "bad" if you quit a winner.