How to properly handle trolls

So out of my last 5 games ive had 2 troll picks. And this is ranked too. In my 5th in final promo to decide if i get to go to gold or not, we have someone lock in jungle caitlyn. we didnt verbally abuse her or anything just let her do her thing. I check her score. its 2-7. since it is my last promo game i tense up and just start asking why me. and she came back with "just cuz im not playing a meta jungle doesnt mean u can verbally abuse me". while that is true in some cases, theres a difference between "out of meta" and "just plain stupid" no clearing abilities, no tankiness, no gank potential. etc. few games later i get azir adc. no joke. and he is flaming me because he is doing stupid things and expects me to ult (i play shen as he is my main). and there is no way to report them for bad picks/troll picks. i mean if someone locks in a champ and feeds or doesnt belong in that role, if majority of his team report him under the new "troll/bad pick" selection, they should get banned for a full day. also possibly refund half the lp lost/forgiven loss in promos?