When all of the buttons disappear you've been desynced with the server and there's nothing you can do but close the game and take the loss. It won't even save the enemies that you have defeated. If CG responds they will post links describing steps to ensure your wifi is strong, etc... but everyone knows that is not the issue at all. There are lots of interactions like this that break your game. Some are very easy to replicate (use cere's second special on a character with damage immunity) others occur generally when certain interactions happen that interfere with a character's animation. SEE's ult sometimes causes it, having too many assists against dark trooper, GL Ahsoka even did it for a full year before they fixed it. And then of course any given datacron comes with the bonus of potentially making a stable character a game breaker. Pretty cool huh?