A) If device is not charged from very long time, keep the device on charging for 1 hr
B) Ensure to charge the device as it supposed to be charge
C) Charging LED (Solid white LED) should blink while device is charging
D) Only Type-C cable need to be used to charge the device
E) Ensure continuous power supply in socket
F) Charging via Laptop or computer is recommended
G) High Power charger will cause damage to the battery
If the headset still doesn't charge, try with a different USB cable that is suitable to connect to your headset charging port just to clarify whether the issue is from your current charging cable