Why does this game always needs special treatment. Happens everywhere, it even was on runescape back in the 90's.

You have blacklist and you can blacklist on Discord and on other social media chizzle too.
If they stalk you in real life go to the police.
Problem solved.

I've been blackmailed & stalked myself (wasn't due online games though), set your pride to zero for once and go to the police. They where always kind enough to solve it for me.