Obviously, I don't suggest this as a first response... maybe the dream of being an author was the one thing still anchoring her to reality? I would seek legal council on the best method of just making her go the hell away (harassment charges/restraining order).
If she persisted to be a thorn in my side, or I had no legal recourse to the harassment, then yes, attempt to ruin her. What other choice do you have? Just allow her to chip away at you for all of eternity?
Delusions have never stopped a sociopath before.