When placing in the charger, a graphic usually appears on the screen. If, as you say, it's completely dead check;

• The charger - does it have an output?*


• The charger/remote connections - clean them nonetheless.


• The battery - is it actually charged?*


• The battery/remote connections - again, clean them anyway.

If none of the above resolve the problem I can only assume it's within the remote itself.

*(Multimeter obviously required).