Intentionally Griefing

In the lobby I got adc first, but some guy couldn't handle it. He chose Anivia and ran Smite and Teleport. As we were leashing he stole the junglers buff with his smite then proceeded to come down to bottom where he would constantly block me off with walls, so i couldn't run away from the enemy ADC and Sup, and would either get poked down, or die completely. I have Screenshots of the chat and have video evidence but cannot find a way to upload them. Can someone please look into this as he has said he has done this before.