How do I defend myself against a horrible roommate?

There are SO many examples, but recently, she has been leaving our patio door all the way open when the air conditioning is on. I wrote her a note last night saying "when the AC is on, can you please only leave the patio door cracked?" (i have a cat that likes to go outside) She responded,"also, if we do that, pito (my cat) needs to s**t/pee aswell his box is outside. also, pito s**t on the carpet and knocked over your flowers" I don't expect her to clean up my cats poop but she left water all over the floor! why can't she just be like "SURE" or "OKAY, SORRY" ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhh should I write back, or be mature and leave it alone, like everything else...