If you suddenly lose your game progress-- don't worry! There are a few ways you can get it back.
1. Simply uninstall and reinstall the application. Once the application is reinstalled, you will see accounts that were previously were used on your device.
Scroll through the accounts to find the correct account (Tip: this is normally the account with the highest level).
2. If the above method did not work, but you were logged into your account via Facebook, you can recover your game and progress by logging in via Facebook again.
3. If the above method didn't work and you can't recover via Facebook, then just send us a support ticket explaining that you are trying to recover your account. We'll ask you a few details to make sure you're the account owner and send you a recovery link. The link will expire within 24 hours, but not to worry, if for whatever reason you can't use the link within that time frame, we can send you another one.