Do you have another lead and charger you could try? Or could you borrow one? It doesn't need to be an LG one as most chargers are interchangeable and the device will simply draw the current it needs. It that works, try your lead with the charger that works and see if it still works - if it does, it's your charger, if not, it's your lead. Replacements for both are readily available but, if you're buying a new lead, make sure it's heavy enough to take the charge current.
Above all, try not to let the batter go flat as this won't do it much good and there's a small risk that it may stop working altogether (although recent phones do seem to have worked round that).
If a new charger and lead don't work, you'll need to get the device sent off for repair.
