Well you will need to catch his name when he first connects. If so then you can check your server log files for that first name and ban his ID and or IP.
Also you may be able to find a plugin which does not allow users to change there name so fast.
<@TimeX-NFo> Hey, we used to have to carry our packets to the servers.
<@TimeX-NFo> And it was upstream, both ways.
<@TimeX-NFo|away> You're asking the old dude for help?????