PS4 Controller won't turn on, but says battery is full when plugged in

I’m currently fixing one of my customer’s controllers in my repair business, and there’s this problem by which I can’t solve on my own. Apparently, my customer dropped his controller after I fixed his ghost issue on the left stick. With that being said, the controller does not want to turn on. But when I plug in the controller to a PS4, the battery indicator says its full. Once I unplug the controller, it shuts off immediately. Is there a fix for this?

Thank you!