1.If this person is chasing you,disturbing you as well blackmailing you then unless you raise protest and take recourse to law .
2. So either severe all communications from him including changing your number .
3.If even this does not deter him from indulging in illegal activities go to the police and lodge complaint of stalking,blackmailing etc.
4. Once FIR is registered there would be immediate stoppage of your torrents.
Decide and act accordingly.