Is it ever ok to get revenge on a narcissist or did I do something stupid?

He was a user and a lying narcissist. Even worse, he was co-worker too. With the help of two friends, we got him fired and kind of ruined his reputation.

I've blocked him but suddenly I received a text from another unknown number. It read ''Hi (my name) this is our secret, I know what you did.'' If a narcissist enjoys using others is it ever ok to get revenge did I do something stupid?
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Now I'm reading these type of people will ruin you more for trying to ruin them. Part of me feels I just did something stupid. This isn't just a typical jerk. This is a real life legitimate narcissist.
Is it ever ok to get revenge on a narcissist or did I do something stupid?
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