Water disconnected, but tub keeps filling up with water?

This is an older model KitchenAid dishwasher that was not being used anymore. Everything was still hooked up, however. Then I started smelling this nasty odor & I tracked it to the dishwasher. The tub was full of this nasty black water. I got all the water out & sanitized. Then after awhile, here is the tub full again & stinking the place up. Had a plumber come in & disconnect the water going to dishwasher. It is still filling up with water. How is thiss possible? What can I do to remedy this? I can't afford to have someone remove it and then fix the big hole in my cabinet. Help?