Freezing in games

In many of the games I have lost, your system has locked me out of the game without notifying me.  This usually happens towards the end of the game, and I am tired of it.  This never happens with other online chess sites, and it seems to happen most when I am winning a game.  I will not play on your site again, and I will recommend to all that are interested in playing chess online to avoid www.chess.com like the plague.