Misgendering someone just because they mistreated you is not ok. Using the correct pronouns for someone should not be a "reward", it says a lot about your character. Stalking is horrible but there are other ways to express your anger rather than being transphobic.
I think you're taking this personally when it has nothing to do with you. They purposely have DEADNAMED me. How's that for transphobic? They REFUSE to use my preferred name.
Misgendering someone just because they mistreated you is not ok. Using the correct pronouns for someone should not be a "reward", it says a lot about your character. Stalking is horrible but there are other ways to express your anger rather than being transphobic.