Grandma stole boyfriends Pokmon cards & sold them (??)

Location: Michigan

I had moved out in February of this year, kinda. I had brought up the idea of moving out to my grandmother, and while at school she packed up my whole room. Supposedly.
I had talked to one of my trusted social workers who knows my family situation, and she said it would be best to have the cops there on my behalf incase things escalated.

Now when i get out of school, my boyfriend and i were parked down the street waiting for the cops.
Once the cops arrived, they escort my boyfriend and I to the property and my grandmother immediately yells that my boyfriend isn’t allowed to step foot on her property so, one of the officers escort my boyfriend back to his car.
I go into my room and see that everything is completely bagged up outside of my room. For context my room is in the basement and it’s “walled” off with curtains. All of my stuff was in bags right outside of the curtains. She had immediately started telling the officers that I’m not allowed to go into that room. And I asked, “what if there’s stuff in there that my boyfriend or I have bought?” One of the younger officers who knows my grandmother replied, “she said you can’t go into the room, you can’t go into the room. It’s her house and we are only here as a civil matter.” Other officer chimed in and said, “you would have to go to court for that.”

Eventually I get all my stuff and I get to my boyfriends family’s house and I see that I’m missing stuff of money value.
For example:
-$168 worth of quarters + coins from my boyfriend’s grandma and father (collection)
-Pokémon cards specifically ones that “looked expensive” (in words of my cousin in her custody)

I just want to know if I can take any legal action towards her?? She has made my life miserable for 4 years and is still trying to control me and my life after she essentially kicked me out. What should I do?

Author: Alarmed-Badger-7346