how to report directly to riot outside the game?

For those sorts of behaviors, they are best handled by the post-game lobby. You have the option to report them there. While Riot Support will sometimes handle certain reports, they generally do not address those that are covered by the report categories in the post-game screen. The ones they deal with are typically those that require screenshots to corroborate, or are the more serious of infractions.

https://support.riotgames.com/hc/en-us open a support ticket, make your arguement riot will not inform you weather they were punished or not however