So guys I live with my mother in law. I live in an RV on her property. We don’t have water or the sewage connected so we just sleep in there for now. Until we do have everything working. My mother in law lets me have food and stuff in the outside freezer. But my sister in law grabs some of my groceries and takes them to her house and she has done this several times it’s quite aggravating to say the least. I go to Costco so I’m okay with my mother in law her son and my father in law to grab some of my food because it’s there house but my sister in law doesn’t live there. I told her not to and she texted back saying “ It’s my moms house so I’ll take whatever I want”. I replied with that rude and disrespectful and my husband and I have been cutting finances short and we are trying to save money so we can move to another state and buy a home. She use to struggle when she had her own place so I thought she would know better then to take groceries they aren’t free. I don’t know what works she lives in but it’s taking me a lot not to break her face in. Or bark my ass off at her so she can get a hint. But I am adult any advice ???