Waiting For Stats...
This is an ongoing issue where ranked games will not give credit for win or loss after freezing on a black screen when a game ends. The games do not get credited after any duration of time; it is not simply a delay.
This happens most often on ranked 3v3s. I reported it months ago and submitted a ticket at that time as well.
It is still not fixed and happens in around 5-10% of games.
http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2176770421/228351900?tab=overview
My team won that game, it shows in match history as a win, but no LP was credited to either side.