"I'm sorry I said/did X and I'm sorry for the harm it caused."
"I'm going to [actually useful action of prevention or goodwill or compensation or amelioration]. Going forward..."
Don't argue with the people you've harmed.
Don't "apologize" for their reactions (vs your actions).
Don't defend yourself. Not even if your feelings are super hurt and you're really sad and you didn't mean to mess up. It's not about you right now.
That is their decision, and you have to abide by it. Forgiveness isn't automatic.