The game is programmed that way.
Fair warning: You are asking this on a site that really doesn't care about online rankings much. We care about ragequits, but the rankings, not so much.
I do feel bad for you, don't get me wrong. But it is what it is. People will ragequit on you and the game is programmed to give you the loss. Not much we can do except notify NRS of our displeasure and hopefully get that patched out.