Chest available

season 1.10 is soon to arrive and riot still has yet to figure out this proble. under my client profile at the lower left i see a note that educates me about my chest availability. nontheless, its proven itself to be a lie. This is what it saids; "Get an S- or higher by yourself or with a premade to earn chest." I have done this multiple times yet it continues to fail me. I dont know how i'm suppose to unclock chest when RIOT is lying to me. I need help. Anybody knows how to explain this to me? please explain this to me. Maybe i'm not understanding correctly.