Two things:
- The notifications that a player you reported has been punished
These notifications go out to players who reported the game that triggered that final review that dealt out punishment.
For example:
Someone else reported Game 1 for player X
Someone else reported Game 2 for player X
You reported Game 3 for player X -> BANNED
You will get that pop up notification that the player has been punished.
You reported Game 1 for player X
Someone else reported Game 2 for player X
Someone else reported Game 3 for player X -> BANNED
You won't get a notification that the player has been punished even though you actually did contribute to catching a toxic person.
- Your punishment
Unfortunately since we don't have chat logs or your punishment history, I don't really have any feedback on your ban. If you would like feedback to see if you indeed were toxic or if this may have been a false positive, post your chat logs and people may be able to help you figure it out.