Question on Punishments for something

Ran into a player who qued for ADC and support. with 2 accounts.

So they are doing the bot lane duo with 2 accounts so they are unable to control both characters at the same time.

Now if they did this is a 5 stack that would be one thing, but the player did it in a 4 stack so they have 1 player who isnt on board with this bullshit (This would be me)

Now im the jungler. So i have a 4 stack trolling me where 1 of the players is controlling 2 champs at once purposely ruining the game for a random player.

What kind of punishments will this person get and what should i report them for.