I dont know the exact age of the unit. but the factory code is 900074. It is plugged direct into a 240v wall socket. The power light comes on when the machine is switched on at the on/off switch. No other lights come on and the unit makes no sound at all.
Is your unit more or less like this?:If so, it is a Delonghi Aria Dry Combo dehumidifier.Assuming that to be the case, and all the other facts you have presented, plus given the unit's non-responsiveness to the manipulation of the three controls on its control panel, then I would say this is a clear case of fan failure in the device. It can't dehumidify if air is not driven through it, and you say there is no noise of a fan active in the device at all.
Check whether the device's fan is blocked or jammed by anything, if you can.
(Would you be interested in repairing the device yourself, aside from the above?)If the unit is young enough to be within a year or so of its purchase date, then it might be still covered by warranty provisions from the manufacturer. To make a failure-within-warranty claim on it, you would need either the sales slip or some other proof of purchase date (such as credit card records, if it was bought with a credit card, for instance.)