I have been in a few games where someone disconnects after getting about 6 cs and reconnects 2 min b4 the game is lost and its cost me bronze 1 promos twice is there nothing that can be done about when someone disconnects mid game i hate losing because a 4v5
It happens dude, it can be frustrating but the only thing that can defeat afkers is pure mathematical power. For example, there are 5 players on each team so there is a 1/4 chance of someone on your team afking (1/(5 players on your team minus 1 you = 4) and a 1/5 chance of someone on the enemy team afking. Therefore, statistically, by spamming more games, you have a better chance of ranking up past bronze (the same applies to any elo, I am currently dealing with regular afks in Plat league). Also, if you try your best every game, winning a 4v5 is not always impossible. At the end of the day though, I can sympathize with you that 4v5s are not always fun especially when others on your game completely give up.
You need to learn to stop taking this game seriously. League was made to be a casual game. The competitive ladder is complete and utter bullshit. You can provide proof of someone trolling directly to rioters and they won't give you back the LP you lost. Honestly make an account and troll on it in ranked and see if you get banned. As long as you play every other game without trolling your account is fine. Just dont swear or say anything in chat. Literally i was in your shoes and when you ask for help from riot's support staff which is going to decide if you stay as a player or a troll they tell you "just report and the system will take care of it" but they dont get reporting the guy literally does nothing for me. If anything it wastes even more of my time writing up a report, that even if he gets banned serves me no purpose since i wouldn't have even seen him again in my games. Like honestly trolls enjoy this game the most and until riot finds out how to deal with him thats the way to play this game.
But think about how much games you have won because enemy team had an afk or a troller. It should be pretty much equal. I have also had trolls and afkers a lot, but then in some games enemy has one of them and it pretty much balance everything.
