People taking other roles and then say they didn't in the game

I didn't have a picture; because I didn't think much of it in the que but I just had a game where someone took my role and completely ignored me since they were a 3 man pre-made that talked with a huge superiority complex and said in the /All chat that they didn't and EVERYONE believed them; The other person on the team bandwagon-ed with them too. It didn't really bother me but It tilted me alot to right now It makes me feel almost bad about myself that I let it happen to me. I don't want to play the "victim" game because I said some mean things to them too but it's just really, really getting under my skin.

This made me REALLY frustrated.