Smurfing

So i just finished a game, 20 lp short of my silver v promos, and we got absolutely stomped by this diamond 1 smurf, actually diamond 1, because he linked his twitch stream to the chat...then i looked at his accound, and he and his 4 man team have been completely destroying low elo people for a while now (the list goes on)...I heard them talking about how much they like to "steamroll bronze noobs" and that they have several of these kinds of accounts...this is beyond pathetic, but there is nothing I can do to stop a terrorizing team of high elo smurfs. i'd very much like a way to get accounts from people like this banned because ruining the game for people that don't play it as much is no way to be doing it...very immature, to be honest.