He likely read the ban message wrong, mosty likey it was "banned for running a botnet" or some such message and/or infering u cant come on using the same ip twice.
I got a message that I was running a BotNet more than once... I know for sure that I was not infected with any trojan or BotNet.
Just try conencting to another server on that network or replace your IP by disconnecting and reconnecting the internet (assuming that you have a dynamic IP).
