I once told a story on here that beats y'all.
I once told an ex-girlfriend that had called to tell me she had brain cancer to call up her fiancé and tell him about it. Then I hung up.
Backstory:
This girl had strung me along for a good four years, on and off, up and down, and had even cheated on me. There was nothing I had left to offer her.
The actual words I used was, "You have a fiancé for a reason. Shouldn't you be talking to him about this?"
That's pretty low. I don't know of any ex's I'd have done that too.