Ok guys I need some help. I have 2 cats, male is 2 years old and the female is 9 months. They both have their own room with their own litterbox. Problem is that the female cat has NEVER used her litterbox. I've tried paper on the litterbox, sand, small rocks... nothing works. She always shits and piss on the floor and its becoming a big problem and also the male cat is starting to do the same. He even shat on my couch, thing that he never did before. What do? How can I teach them to use the litterbox again? Any advice would be appreciated.