Why is my ping so high when my internet works perfectly fast?

It happened since today morning. I tried rank games and the game just freezes and disconnects eventually. I lost my lp and I thought my internet was wrong.

I first tried to turn my mac off and on. Didn't work I reconnected wifi. Didn't work I contacted ISP. Had no problem, they said.

So I played again, with hope if the game works now. But it breaks again.

I seriously wan Riot to either fix this bug as soon as possible. I want my lp back as well. If can't, at least remove my afk penalty because it is 100% not my fault.