If your display doesn't show anything, it's probably that the connector got loose.

Worry not, it's super easy to fix :)

It's on the back of the Gamebuino, to the right of the battery. The cables comes from underneath the battery.

1- Pull on the black thing to get it loose

2- Put the orange ribbon cable back in the connector as much as you can

3- Push back the black thing to lock the ribbon cable in place