Need advice pleaseee ):?

So I think my relationship w my sister is really bad. I did want to reconcile but not anymore. I completely do not want to have any contact with her. She makes me feel like ****. She's 18 & Im 20. A couple months ago, we got into an argument & haven't talked since. Basically, I simply told her to clean the cat because it was dirty & she was leaving stains on the carpet & on my bed. Well, her response was: stfu & leave me the hell alone. That really annoyed me. So I said how dare she talk to me like that when I didn't even ask her rudely & I even bought her some clothes; because she didn't have $ & I felt bad. Then later she goes on to say that I only said that because I was mad frm the day before since she asked to use the laptop & I didn't want to give it but I still did. Today after I woke up from a nap in a room beside our room (we share a room), I go & check my stuff cause I knw she used it while I was sleeping& she was getting ready 2 go out. Then I dumped my pile of dirty clothes into a bin our mom gave us to use. She takes it out & throws it on the floor. I waited but she didn't put it back so I said this goes inside loudly & put it right back. She then dumps more clothes & even kicks my stuff. She even said that the bin is hers because I already have 1, which I bought myself to use 4 school only. Just wow. Her side of the room is always messy & dirty while mines clean. I got SO mad that I started tearing.. I would love some advice guys on how to resolve this ):