Brawl Draft is a one-person project, so there is no support desk. Everything that comes in does get read. Pick whichever channel fits.
The best place for anything about the tool itself is the public issue tracker: open an issue on GitHub. A recommendation that looks wrong, a brawler or map that is missing or misnamed, a page that will not load, or something you wish the board did. Filing it there keeps it visible until it is fixed, and existing issues are public too, so you can check whether yours is already known.
The source code is open under the MIT license if you would rather send a fix than a report.
For a recommendation you think is wrong, the map, the mode and the full state of the board (bans and picks, in order) is enough to reproduce it. For anything to do with your roster or rank, include your player tag. It is public game data and the only way to see what the site saw. A screenshot never hurts.
The Privacy page lists what the site stores and why. It is short, because there are no accounts and no tracking cookies. Anything it does not answer is welcome through the channels above.
Brawl Draft is unofficial fan content with no connection to Supercell. Questions about your account, purchases, in-game bans, or anything else inside Brawl Stars need to go to Supercell's own support, not here.