This site has your product manual for your dispenser but it is very vague on trouble shooting the cooling system.
In general, the compressor is controlled by a thermostat that is usually located in the conditioned space. It cycles the compressor on and off based on the sensed temperature and the setting that it is adjusted to.
So, let's talk in general refrigeration terms. Where the compressor is located, is there a fan? If so, is it running? That fan is usually the condenser fan and is wired to come on anytime the compressor is supposed to be running. If the fan is running and the compressor is not, then there is an issue with the compressor. If the fan is not running and the compressor is not running, then there is an issue with either power or the thermostat. If the compressor is running and the fan is not, then there is an issue with the fan.
This is a good starting point. Let me know if I can be of further help.