Ah yeah sorry, Brave doesn't support paid extensions. It's a known issue with the browser. I usually direct Brave users to download a release package directly: https://github.com/mikecrittenden/shortkeys/releases
Feel free to shoot me an email (in my profile) with your order number and I'm happy to refund you.
Its no problem, i got it working from the repo, don't need a refund, it saved enough mouse clicks for me today to make me happy! I have carpal tunnel and this made a difference today. You may want to include a template of hotkeys that people use or create a default set to get people going.