Premade trying to force me out of my role in flex

So I was playing flex with my buddy and we got into a lobby and the jungler ask if he can mid I say no. I was already hovering my champion and the ADC bans my champ {{champion:245}}. The guy pretends he did not see and said he meant to ban draven. The jungler asks again if he can have mid now that my champ was banned so I was skeptical. I do a quick look up and see that they are premade. Is there a way to prevent this kind of abuse and should this be a reportable and temporarily banned offense (I would say yes). I ended up playing Ziggs and we won the game by a landslide but I still do not like this kind of behavior, and why would anyone think it is ok to force someone out of a role?
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