Ranked Promo bug

I just got into my Plat IV promos, and I had played 2 games after reaching 100lp. I won one and lost one, so I should still have a third chance to reach Plat IV but for some reason, immediately after losing in the 2nd game, I was told that I was unsuccessful in my promotion. Can someone fix this please, I wont play another Solo/Duo until I receive some feedback.