This player asked for mid, then banned our mid's pick intent when they said no

Is this reportable, given that the pre game chat isn't saved? Even worse, someone on enemy team dodged before the game started, thus cleaning up any evidence that this player did this.

In the remade lobby, the player did the same thing, but also stole the pick this time.

Third lobby, I (support) was queued with this player again, but without other players on my past team (presumably they just dodged and re-queued). The player got top again, but our mid was willing to swap.

Please tell me this is a reportable offense. I can provide the username privately if necessary (currently saved elsewhere, since I can't name and shame). I have no screenshots or other evidence, though.