There are a LOT of channels unmoderated in the matrix directory that could have been reported, so this isn't surprising. I have abuse complaints emailed to your abuse address that have gone unanswered, so I don't believe that you're taking your terms of use seriously.
You can find my complaints in your inbox. It's good to know Google is taking action - will send the same complaints to them in the future since that seems to get more of a response from the devs.