wireless ceiling fans with low voltage
Your problems could be with the remote control receiver unit. These have power control circuitry inside that allows for on/off control of the fan and light and possibly speed control for the fan and dimming for the light. As with any electronic circuitry connected to the power line these can be damaged by a surge or serious spike on the power line. 

One common cause of spikes and surges in some areas is thunder storms with accompanying lightening. You may want to look into swapping out one of these receiver units with a new one to see if it corrects the problem.

Note that this type of unit is permanently connected to the AC mains exposing it to storm surges all the time. In some instances the fan/light fixture may be wired up through a switch to shut it off. In cases where the switch is off during a storm it could account why some units escaped damage whilst others have failed.