

I understand your frustration and I, too, thought that blocking went both ways before seeing your post.
If you encounter someone who is harassing you and attacking your reputation without your knowledge and down voting your whole history, you should gather the proof and contact your instances mods. There’s a very good chance they’ll ban them either temporarily or permanently from the instance. Or contact the mods from their instance as well.
Anyway, I hope this helps.
Let me start a team for my team in Teams.