Explain that the damaged component is a separate control accessory and provide its identity as well as the disposer model. The repairer can then confirm whether the visit needs appliance expertise, electrical work or both.
What the observation tells you
Do not open the box or bypass it to prove that the motor runs. Water damage, overheating or a damaged cable requires the appliance to stay unused until the arrangement is assessed. A functioning surface button does not clear a damaged box for use.
A useful next step
Ask the service provider to confirm the scope before attendance. Manufacturer warranty or safety-notice work may require a particular authorised route.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.