I was grouped up with a 4 man in norms that all simultaneously left the game to have me 1v5 twice

This happened twice during this game. And the messed up thing is I don't even know if anything will end up happening to them over it, because they were in a 4 man so they obviously wouldn't report eachother, and I'm pretty sure the enemy team didn't mind the free win so I doubt more than 1 of them reported. The game didn't detect it as 'AFK' because they all joined back a while after during the game and when they left a second time they all joined back JUST as our nexus blew. I don't know what to do if the reports don't do anything, but this is some bullshit to happen, norms or not.