They do, at least account wide they do , when it was 4v4 my friend got ddosed, he texted me that his whole internet went to crap, even his roomate watching netflix cut out. Then a round later a rando got kicked aswell. (Messaged him after the match , he said the same thing, entire internet went to crap) So i came on here , used the report tool, linked a youtube video i uploaded of them ddosing , asked my friend and rando to report them too. I then messaged the guy calling him out on cheating, no response. 1 month later (literally like 32 days since) the guy i called out messaged me back cussing me out, asking me to 1v1 him on his new account. I checked and it was 26 days old lol, i also checked his old account and it completely vanished from here, like it got deleted. i even visted the post game report on here and clicked on his name and i got a little message saying this user doesn't exist anymore. Shame, it was a 4 year old account. Also another quick example, last season one of my online friends got a warning for bad internet connection after a comp match, people were reporting him.

You're not alone. I don't believe they do anything.