When one of your team-mate is so negative

Since its a blind match, i usually went for supp since i had a higher win rate with him than any other support champion. top already annoyed since champion selection cos of my choice. My boxes prevent enemy team from clearing objectives, even occasionally my boxes pokes the heck out of enemy players alot before they can even start an engage, still Gnar being so negative and toxic towards me. Our just went afk and dc mid game and never returns for some reason. Again Gnar being so negative and kept typing surrender cos its a 4v5 game. But in the end, we manage to secure victory yet Gnar still do not believe my Shaco support works.....