What to do when noone cooperates

Hello guys, im diamond V in solo que, but im trying to reach diamond in flex too. And my question is, what should i do when people just play alone? Last game i played a Sion top game, all lanes won and almost everyone played great. But our Xayah, never came with us, she said she cant with an autist smilie: I cant XD (but in lobby spamming her stream with 2 viewers and wondering why noone watches her) Later, our mid didnt follow us, we were 4 mid and our bot was pushed into our inhib, Rammus pinged that he clears it when he respawns, but no, our Ekko recalls, i ping the other 2 to leave mid, ofc they dont listen, get swarmed, and we lose. Seriously, we were so OP, but still we lost because noone helped each other, guys, what do you do? I cant control their champs, i can only ping and write in chat...