The ban should expire automatically after a few hours, so it has probably expired already. If not email
help@austnet.org explaining the problem and including what you've pasted here.
Be wary of channels people tell you to join. Also, be sure to /mode #chan the channel if you really must join it, if its empty ('no such channel') and someone is asking you to join it's probably a fair indication you're about to walk into an automatic ban.
Hope that helps