Hello,
As previously mentioned you can report the player(s) ingame during the specific match,
If you missed the opportunity to do so and have a screenshot and matchID for me, you can also report severe cases to me personally, but this is not the usual way to do so. Please prioritise the in-game report system.
You can get your matchID in-game or find the LID number on trackmania.io
Use your own judgement, but my DM's are always open,
Discord: Phoebe#8272
Twitter: Phoebevelde