I won my promo game, but it gave me a loss

I was 1-1 in promos playing a ranked game. I was 7/2, then my power went out and by the time i reconnected, 15 minutes had elapsed. Even with this set back I finished 8/2 and my team won the game. There was a victory screen and I got a win in my match history. However, it counted as a loss towards my promos. Riot Please Send Help.