I tell this to a lot of people: if there is a problem that you cannot fix, try booting the device into its recovery mode and then taking a factory reset. Another option you have is to flash the stock ROM manually. New software updates will fix bugs, but if you need something fixed right away, you can flash them manually. Your ROM is here: https://consumingtech.com/download-karbonn-firmware/

Hi catty. Try to reinstall the battery. Works most of the time for me.