What is the legitimate Islamic course of action a woman can take against a colleague who is spying on and controlling her computer, despite her having warned him and resigned?

What this person is doing is transgressing limits, violating sanctities, and spying on Muslims, all of which are manifest prohibitions. Therefore, the violated woman should seek help from one of her relatives or his relatives, those known for their goodness and righteousness, to restrain him from his wrongdoing. If he does not desist, she may then seek help from the responsible authorities.