Feeling stuck with overbearing Nmother

Feeling stuck and looking for advice on setting boundaries. My mom has been showing up at my apartment uninvited despite me going no contact over a year ago. Today, she followed me from the cafe to my apartment and kept trying to hug my waist, not out of affection, but in a way that felt controlling and invasive. I tried to break free, but I ended up feeling reactive, and security didn’t intervene. He said it's not his job to to intervene family affairs.

I’ve heard about the grey rock method and am wondering how it applies when someone keeps crossing personal boundaries in ways that are hard to ignore. Any advice on how to manage this situation without feeling like I’m always reacting? How can I stay firm in my boundaries without feeling trapped?

I've already escalated this issue multiple times to management office, no action..