How riot bug cost me my pormo

So I was in silver flex promo game with 1 win and 1 lose. Went in with 5 of my friends. One of my friend disconnected and we were going to remake, when it was 3 min we couldn't remake. We weren't playing normally due to thinking it was remake (as many have done). By the time it we realize the game is gonna go on normally it was too late. This might be because of 5 person flex and avoid loophole. However, when I went out it immediately showed 2 lose streak and that I failed promo. I went back to check if there was a game I forgot about and no, the last game I played was a win, and I played the one game after that resulted in two lose. I don't play flex that often so when I get the chance I wanna climb the latter.