M70 schaltet sich nicht ein

Our new M70 is fully charged. However, the phone is dead, as soon as I take it out of the charger station. Now we have just registered this M70 phone to our M900 , whilst keeping it in the charger station.  As long as I keep the M70 it its charging station, the M70 wokrs fine. As soon as I take it out of the charger, the phone is dead again. Whatever key I press, nothing happens, the display stays black. As soon as I put it back into the charger, the phone wakes up. 

Any idea?