You probably just gave someone your personal information and password if you replied to a message like that. Unless such messages come from NickServ or another valid nickname service on the network you're using, you shouldn't reply to those. Whatever you typed probably gave them the personal information and sent out some spam message that got you banned. If you use the same password information ANYWHERE else, you should probably change it.
As for removing the ban, you will have to contact the network and explain what happened. You can find contact information on their website - use google if you don't know their website address.