[Hextech crafting] not getting chest when owned champion is on free to play

I own and he is also on free to play rotation. I just finished a ranked game and I got S-, but no chest were given to me. here is a picture showing that I have not gotten a chest despite getting S-.

http://i.imgur.com/ffS2mr5.png

As shown in the picture I have gotten S- but the chest is not obtained. I feel like Riot is purposely screwing me now. In the same game we lost because garen afk after 5 minutes, and now I got S- but no chest for me. RITO PLZ