did you click on 'draw' after the 50 moves had elapsed ? just as in a OTB game, you must 'claim' the draw, the TD (system) won't automatically award it for draws where player action is required.
the system will automatically award a draw if you and your opponent play down to just two kings, or king and knight vs king or king and bishop vs king.
regards,
I recently played a 240 move game. It took me almost 200 moves to mate my opponent :). Interestingly, the game did not end in a draw due to the 50 move rule.