JamalSmalls

I recently bought this slightly used casio px 160. It now has a stuck key, when you press the key to the bottom it makes a sound, but it gets stuck there and will not come back up. Usually when you press it when its stuck down it will not make a sound. Does anyone know how to fix this? I did some research and thought that maybe it is the hammer key cap that is worn down, but I am not sure. Video link : https://imgur.com/rYdfhmW