If someone has shown you they do not appreciate what you bring, there is no point in convincing them to see what they do not believe. Your absence should be the only thing to speak. Time will then shine light on the truth, and there will likely come a time when they acknowledge your rarity and reflect on how they treated you. Let them sit in the static of your distance and lack of acknowledgement. You gave too many chances to willingly repeat the cycle of disappointment. Make the statement clear that their venom is not welcome. Your energy is your currency, so why should they be cashing in?