Sounds like a blockage. The first step is to see if you can get out whatever is plugging it without having to call the plumber. You can buy or rent a "snake" for drains. It's a coiled up wire found at the hardware store. Run it down the plumbing until you can bring back the gunk plugging up the works. If you go all the length of the coil and still nothing, call the plumber. It's a professional job, best left to those who eally know what their doing. But the snake solution works most of the time. Link and balls get carried out with the drain water, eventually clogging up the works. A little "snake" action is usually all it takes to get it unstuck.