My lumia 620's battery went critically low and turned off. I plugged it in charging but even after 3hours it didnt turned on, with only the charging logo flashing. As soon as i remove it from charging it turns off.. Itz just been a year since i bought the phone and the shop where i gave the phone for repair says battery is not of any uze. He tried a new battery bt the phone is still not switching on. Please help, i think there's no problm wd d battery. Please help , how to turn it on.