I get the impression that $USER's contacts over on masto.soc did not know that they could no longer receive $USER's notices. #Blockwars continues to stir up messes long after most people have lost their taste for the topic.

The solution is simple: keep accounts on a couple of instances with different admins and different moderation policies, so you don't unknowingly lose contact with your contacts. Even better if you can self-host one of those accounts.