Roommate living

So my cousin and I lives together. I'm a female of course. He's a male. Am I the only one who think it isn't right that he leaves his company here while he's gone to work and such? I work 3rd shift 11pm to 7am). So I sleep during the day and he goes to work at 2pm while I'm sleeping. When I awake I hear people in the kitchen, warming up food, going on the refrigerator and things. I told him that his company needs to be occupied when he's here. And also told his mom that I told him. They don't see the issue. I don't be knowing who's in my apartment. My name and my dad's name is on the lease he's just an occupant. His mom said that she neither sees an issue if it's a girl that's left here. I don't see the gender making a difference. People are people and at the end of the day I don't know the friends he leaves here. Am I wrong for saying anything? I told them I didn't want any bad tension but they are dragging it out and making it a big deal. It's been hours and they are still texting me about it. I told them I wasn't mad but now they are making me mad. Because I said what I had to say and left it at that. Who's wrong?