How do we deal with academic bullies aka toxic professors? - 25 F

I’m a public health student who’s always tried to contribute to my university through volunteering and extra-curricular activities. I’ve been helping professors with extra work, but one professor (40 M) —who taught communication and research methodology—has been harassing me. He’s constantly crossing boundaries, making inappropriate comments, and using his position to try and control me.

After I fell sick and had to decline a major task (anchoring a two-week induction event), he mocked me publicly, defamed me, and even removed me from the placecom. Despite everything, I continued helping my peers behind the scenes, but when I asked him about placement opportunities, he mocked me again.

I ended up going to the HOD for help, and after explaining my situation, the HOD reassured me that the professor would not contact me again. Yet, the professor has continued assigning me work, and when I declined via email (due to academic commitments), the HOD found my response rude.

I'm unsure how to proceed.