Unidare Storage WMX718N?

Hallo
Kids left paper over top of model:Unidare WMX718N storage heater cover it 3 days ago whilst the unit is OFF but discharging heat ( still hot) few hours later , a weird smell came out for a short while.On the following night we turned it on to re-charge it, but it no longer working?Can we reset the unit or what part should I change?(main socket is workingfine)I called Unidare, but they do not have the knowledge.Can someone help as it's freezing cold these few weeks, thanks !