People have long memories. They won’t remember those times that you were gracious and kind but that one time you lost your composure.
It isn't so easy to do is it? You have an interaction with someone and it goes south in a flaming, tragic spiral of death. The problem is it hits the ground and is still smoldering and the other person fans the flames. They say things about you trash your name, attempt to humiliate you and try to challenge you to do the same. They create what maybe in their head is their reality but varies from your own. People will contact you and want to know how you will respond to the attacks.
Here is my two cents: Most people are interested in the story and not in you.
I see this a lot on Fet. People have relationships in RL or cyber ones and when it fails for whatever reason they choose to air their grievances with all who will listen as if Fet is a jury of peers who will vindicate their actions in the relationship.
My advice is to take the high road. The other party can keep up their theatrics but after awhile people will notice that you haven’t said anything and that you seem to have moved on and don’t care. When that happens they don’t care about the Punch & Judy show being produced by the other party.
When someone repeatedly keeps talking to themselves people will recognize why you are relieved to be free of that person.
Never sacrifice your class to get even with someone who has none.