Random Invitation from ELO Boosters

Saturday 4:41, 10/21/2016 I was just sitting around in League for a bit, texting some friends, and I was suddenly invited to a lobby by two people I had never before met. I sat there for a while, for I was curious as to who they were. They eventually told me, "Hey, we're starting a boosting service, $40 per rank." Something along those lines. I just responded with, "lol, how did you find me?" and he replied "idk" and as I was pulling up this page to report them, I was kicked. I didn't think of getting a screenshot until it was too late, but I have their summoner names. I don't think that I should post their summoner's names, so I will give them if asked by a RIOT employee. Also, if there's a proper way to do this, can someone please tell me? I tried Google, but didn't find anything helpful.