Many don’t know there are a couple of things that can often be done that may resolve the issue you are having.
1. Under the disposal is a button to reset it. Try hitting that button and see if that resolves the issue.
2. Every garbage disposal comes with a garbage disposal wrench (Allen wrench) there is a place for the wrench under the unit. When the unit locks up often the wrench can free it up and get it running properly again.
*If yours is missing (we think people throw them away not knowing) you can pick one up at Home Depot or Lowes for about $10.
If neither of these things fix it, or the disposal is leaking there is a good chance a replacement is needed.