I'm sorry that you're having this problem. One thing that you can also try is to add some Cat Attract Litter to the top of your current litter. It's supposed to attract cats and help them use the litter box again. You can buy this at Petsmart. It worked wonders when I was having peeing issues. Here's a great link about litter box problems and solutions: http://www.catinfo.org/?link=litterbox. Good luck.