Sister trouble, what should i do?

My sister came over with her boyfriend who doesn't like me to watch the game. Before they left they took some chips i had on the table that i was going to munch on after they left. They took them without asking. I called them and they were laughing about it. It ended up being a biiiiig fight and this was like in May. We still have not talked. Im 28 and she is 22. I took her in when she had no place to go cuz our dad was so bad on coke and i told her she should not even be taking stuff from me without asking. who owes who and apology?