I assume you mean the buttons on the joystick.
I suggest that you plug the joystick into your computer and then run the Gcp_Configurator program that comes with the library. Select the joystick from the list of devices and confirm that the configurator recognises and responds to the buttons. If it doesn’t then there is nothing you can do,
If it does recognise the joystick buttons the I suggest you create a new simple sketch (without Arduino) that simply reads the joystick buttons and prints out some value. Once you get that to work you should be able to get your sketch to work.
More info about GCP can be wound on my website.