All I did was to say that I resigned due to hostile enviroment HR wont answer on mail
Why would you wanna continue contacting them after you resigned
You used a magic keyword that opens up a legal liability threat to them. They're going to refuse to respond without having legal representation reviewing every word. And there will probably be an investigation
Could you elaborate on this
What did you expect them to do? They don't owe you any explanation and certainly no severance because you resigned.