What can I do to solve it?

Hi,

If the system does not get cold at all and you do hear the motor, then you should look for a gas leak. make sure the motor doesn't run for long. It could also be the the motor has sized. This will result in hearing the motor but the unit does not pump any gas.
Call a refrigeration tech and let him have a look. Make sure that the controlling part of the fridge/freezer is also working