thanks for the heads up! i changed my credentials
i'm fairly certain that a malware wasn't the issue -- i reinstalled my OS about one week ago, when i got my SSD, and i'm using linux mint instead of windows now. also it wasn't only botb, my soundcloud was hacked and deleted (same pw lol); i assume the person wanted to delete my BotB account, but since he couldn't, he did what he did.
based on what happened (and how it happened), i think i can assume who did this. i'm not gonna go into great detail (feel free to ask me on the botb irc/discord if you wish), but if my suspicion is correct, it was a matter of trust, oversharing and reusing the same pw in multiple places. definitely a lesson learned here