Disposal Blade is Not Rotating?

It maybe that something has caught in the disposal, preventing it from turning; hence the plastic smell. At the very bottom of the disposal is a hole to insert an Allen wrench. Put in the wrench and turn it a few times. This usually clears any obstruction. Every disposal comes with the wrench. If you have lost yours go to Home Depot or Lowes, go to the plumbing or the area they sell disposals. They should help you buy one. No guarantee this is the problem. It maybe your disposal has died and you need to buy a new one.