I have a male cat, about 10 years old. Ever since the night I got home late from the hospital when my granddaughter was born, he refuses to use his littler box to poop in. He keeps doing it on my carpet. I live in an apt and I can't do anything to replace the carpet. HOW DO I GET HIM TO STOP THIS. I keep his box clean, he pees in there but won't poop there. I am going crazy with it.