Is this punishment fair or too far?

So I live with my grandparents and she has always been super strict with me and treated me worse than my siblings who always live there. The other morning it was my day off work however they rang me and said they needed me to help out ASAP so I didn’t think to make my bed so when I got home she had thrown my laptop at the window smashed all the pictures on my wall and set fire to my clothing and wrote lazy fat pig on my walls in marker because I hadn’t made my bed. All my room is tidy but if I don’t make my bed she goes insane. I have an older brother who’s room is disgusting and she cleans it every day for him. One time due to work again I didn’t make my bed and I came home she had hung up all my dirty underwear on the washing line with all the discharge in them showing people she wanted the neighbours to see how dirty I am just like my room. I am constantly crying and feel like I don’t deserve it