It's long but please read I need advice on a situation I am in with my uncles wife.?

As stated I have lived with them for about three months now and i was looking at schools here to attend but since i moved here in May it was for the January school semester since it was to late to apply for Sept. Anyway during my first few weeks here i had talked to both my uncle and his wife and told them I was willing to pay rent. My uncle of course said no way but my aunt being practical was like well not right now but I will talk to you in the future as to what we should do about it and I said fine no problem come talk to me when you feel that i should. On sat I had overheard her and my uncle arguing about me and at this time i was seriously considering a school i got wait listed for back home when my aunt told me my uncle wanted to talk to me outside i knew there was a problem but when i went to talk to him he looked so upset and said he didn't really want to get into, so i knew my aunt had put him up to this so at that moment i decided i should go home and thus told him so. I said i would leave in a week or two. The next day while my Uncle was sleeping my aunt proceeded to verbally attack me saying i was being ridiculous I was a liar and then when i told her i was leaving to go home she said good. After this first argument i went for a long walk as i was really upset and not sure what i had done to make her so mad at me. Upon returning home she said sit down i want to talk. she said i am pissed of at you, yesterday when we were friend's house to get your hair done that insulting remark you made about your uncle really pissed me off. Unsure of the remark i asked her what she meant and she proceeded to say that comment about the chicken. For the record here is exactly what i said to this women. She asked do you like working at KFC and I said yes its not bad at all and my uncle likes the chicken whenever i bring it home. i don't know maybe i am clueless but i really don't understand how that can be seen as an insult when it was meant as light joke. after i apologized saying i did not mean to offend her which she didn't believe she then began a tirade on how I don't pay rent when as i mentioned before we had already discussed it and it was to my understanding that we came to the agreement that when the time came she would come and ask me. i really don't understand. i am not home most nights until 11 as i work i eat out more then i eat at home and i clean the whole house top to bottom everything so she and my uncle wont have to do anything but their laundry and feed themselves. can someone please tell me what i am missing here?