I have a JD-31 that is not working as expected. When I try to charge the power bank with the USB-C port, one light flashes for about 30s and then nothing happens. The flashlight, USB out etc also do not work. 

I think I need to reboot the device somehow, but long pressing the power button did not work. I have tried 2-3 different 30W Pd3.0 rated chargers with cables that I know are functioning fine. 

How can I fix the power bank?