You need to CAREFULLY check and see if you have any heat in the heating element, Big vertical tube, covered with insulation and sheet metal.
If no. Troubleshooting begins. If yes there is lots of heat, refrigerator removal begins.
The heating element or thermostat or a connector are all suspects.
An OHMMETER check of the element will verify if it blew up and went open circuit.
If an ohmmeter says the heating element is good, the thermostat becomes suspect.