Such problems are dependent on an unstable internet connection between your device and our servers. Don't worry, it's likely not your fault, it's us, and we are very sorry about that.
First of all, if you re-open the game fully right after the crash, you will be able to continue playing from the point where the game crashed - that includes crashes during the Campaign and the Battle Event. So stop reading this if you haven't done that already! Time is passing!
Unfortunately, as a general rule, we cannot provide you with the lost energy/tickets/rewards if the game did not load from the moment of the crash.