I went to the lady on the right and I choose Random Matchup and she told me what she normally says when you shut of you're DS turns off and you wait a hour and you could battle again ,but I haven't battled in weeks what happen to my game ?
It might have been the clock on your DS. The game records whenever you go into the Random Matchup obviously, and so if you were playing with your clock this would be the problem.
Hope I helped. :)