So that person who was selling cheats on his stream. I signed in, went to his profile and clicked on report.

It's about Twitch, reddit does not allow me to add Twitch to the title.

There was no obvious REPORT CHEATER section so I clicked on report external twitch activity.

I clicked that and it gave me an address something like osit@

Wrote an e-mail to them and they responded with a wall of text which was a generic reply that did not answer my question how to report a cheter.