Airpods pro case won’t charge and only works when plugged in to charger

I have had my airpod pros for over 3 years and 2 days ago, all of a sudden, the case and AirPods won’t work unless it is plugged in into a charger. It flashes green while it is plugged in but as soon as I unplugged it, the light turns off and the AirPods won’t pop up on my screen and they won’t respond at all. How can I fix this ?