Jothar: “So my rav was the Chofetz Chaim”
Every single situation is different. They have a call-in number. Id speak to a live Rov and explain what you have proof of, what you plan on doing or saying, and what the chance of change/improvement/effectiveness is. Then I’d move on that advice. Its not that simple. You make it clear that there was no live Rov involved when you shot those hurtful accusatory words.