Lost a game in my high silver series because we were playing with a unranked

not sure where to put this but yea, a friend and i were playing for our series for Gold 5 and everything was going fine,until our bot lane gave first blood and continued to feed after that, long story short we lost and when we looked at our ADC wich did terrible we saw that she was unranked and only had 4 recent matches all ranked, how does a unranked play with high silvers and do terribly, shouldnt the system read that when all of there last 4 games where losses and they fed that it shouldnt put it anything above bronze 2?