If your garbage disposal is not working, then you will need to call a plumber. However, there are a few things that you can try before calling a plumber. If the unit is still under warranty, then the first thing you should do is contact the manufacturer for troubleshooting information and potential repairs. If it is outside of its warranty, then you may need to remove the unit and inspect it for any obvious problems. If you find a problem, such as a broken disposer, then you can replace it yourself; otherwise, you will need to call a plumber.