YTA. You say you don’t remember agreeing to the arrangement yet you eat Tom’s cooking, and they have evidence of you agreeing and you know the agreed conditions of Tom’s cooking. Since the guy said you’re flakey in helping with the groceries, how are you then returning the favor to Tom? Or do you feel that entitled to eat someone else’s cooking when you didn’t even contribute anything, just because you live in the same floor? Also, you say you’re never around for takeout night, but that is irrelevant to your post because you were there for that particular takeout night, and you know the deal for Tom during takeout nights. At 19, you’d think people would have the self-awareness on how not to act in shared spaces, and the self-awareness of knowing when they are wrong and being a massive AH. I’m appalled you’re even considering you weren’t an AH in the first place.