Before arranging a visit for a disposal, there are a couple of things worth trying — and in a house used seasonally, one of them is usually the answer.
Start here
If it hums but will not turn, the motor is fine and something is jammed. Switch off the power at the wall, use the small hex key that came with the unit to free the flywheel underneath, then press the reset button on the bottom. If it is silent, the reset alone often does it.
Sitting idle causes its own problems
A disposal left unused for months can seize and develop a smell from residue drying inside. Running it briefly with cold water during a caretaker visit keeps it turning freely.
Entertaining puts it under load
These kitchens do very little for weeks and then cater properly. If yours jams when the house is full, it is likely underpowered for how the property is actually used rather than faulty.
What it does not handle
Cooking oil and fat, which set further along the pipe and combine with sand already in the line.