Riot do US a favor

I just played a game and had a troll that simply followed me anywhere bc he didn't get a role he wanted. I was playing jg he took my jg and exp. Also abused everyone and did nothing when we were getting killed beside him. Please make a warning or something that PICK ORDER IS HOW YOU GET YOUR ROLES. I just lost LP because of a SINGLE person decided to troll.

Can I have my LP back? Please?