Normal Matchmaking is Garbage

I realize that there is an mmr for ranked and a different mmr for unranked, but what the hell. I recently had a game where there was an enemy irelia and the player was platinum 4. I'm silver 4, our midlaner (who was against the irelia) was unranked but was level 32 so it is safe to assume he isnt as advanced as the irelia. (who was lvl 191 btw.) This was the same story for the rest of my team except for our top laner was gold 4 which is still significantly lower ranked than platinum 4. Our midlaner (a zed) was absolutely curb stomped and when i tried to help him out (I was the jungler) I also got curb stomped. In terms of skill this was an absurdly unfair match up, and she did carry her team to victory. I checked who she played with in past games and it looks like they were queing up with two other people who were ranked similar to me. This felt like a punishment just because of how hard we were crushed by this one player. Is there nothing that can be done to fix this problem? because honestly if this keeps happening I'm gonna quit this game, and this has happened before.