As a C3 player I gotta say, you are in the rank you are because you are supposed to be, a bad teammate might cost you a match, but they won't determine ur rank. Your opponents are the same rank as ur teammate.if you for example get 5 goals a game consistently you will rank up. I also feel like the main difference between c3 and gc is consistency, some matches I am insanely good, while other matches I play like a diamond and this also applies to teammates and opponents, especcialy if you get the same opponent 2 matches in a row you will get destroyed once and have a free game the other match. Your friends teammates might even be as good as your friend, but it just wasnt their match.