It is true, NokiaE5 if low bat need to charge immediately or else E5 will be destroy?

I purchased this NokiaE5 last Jan24,2011 in cellphone store. After few days of using this phone, it got hanged and restarted, wont switch on even the battery is full. Had it repaired from nokia care, it took 1 week to get it back, the battery and charger were fine and normal but the phone Electric's fault problem. The repairman of nokia care said "If low bat, you need to charge immediately or else the battery will drain out of power to destroy your phone, same thing happened and repair it come back here, anytime." They tested another full battery into my E5 but won't switch on and they tested electric power into my E5 but wont switch on again.. something wrong with E5.. Is this really true? The battery is normal and no problem. E5's receipt says "1 year warranty of nokiaE5" but its broken after few days only. What the fail?? Do i have to charge quickly after repaired or else my E5 will be destroy? I didn't know that because i read all the manual handbooks but there was no problem about battery and power... so after repaired my phone went dead again, same problem without say "warning!" the battery is still full. Battery is made by China. im stressed to go back to nokia care..... Pls let me know.. Thanks..