Looks like he said this "xxXfootXxx blah blah blah he is using a mean tag (maybe swearing?), he is making multiple alt accounts to get me banned. PLEASE BAN HIM PLEASE, IP BAN HIM PLEASEPLEASE MORE BEGGING PLEASE HALP".
Do what SlipAnc said, prove it, prove you're saying the truth like taking screenshots in-game (With F6).