Parents trying to exploit me please help

I’ve been living on my own for four years now. I live alone. I used to call and visit my parents regularly but stopped when my stepfather revealed to me that my mom suspected an affair was going on between me and my stepfather. That was such a ridiculous accusation and can’t be further from the truth. I blocked my stepdad in my phone

Well whenever I would call my mom she would get upset at me blocking my stepdad and allow him to get on the phone to flirt with me. She is betraying me and not protecting me. My mother is also extremely verbally and physically abusive.

I told my mom that she and my dad are not allowed to visit me at my apartment and when they stopped by I called the police. they were asked to leave

My mom still keeps pestering me as to why she can’t visit me after I told her a million times no

I am just lost as to why my family is acting like this. I never expected this turn of events to happen. My sister niece and nephew do not care at all

please help. what kind of family is this ?