If you were logged in with Facebook before, then your game state is backed up and saved on the cloud. Start the game without signing in with Facebook account, complete a few tasks and then sign in with your Facebook account and select the saved game from the cloud.
If you haven't been using Facebook login, please try to remember your previous game ID (maybe you wrote emails to us before?) and send us a message with your previous and new IDs.
If you haven’t been using Facebook login to save progress and there’s no information about your previous ID - all we can do is send you the amount of zombucks you purchased earlier to your new account with a +50% bonus for the inconvenience.
If you decide to accept this offer, please send us a message with all the receipts for Zombie Castaways from Google Play/ App Store/Amazon and your current game ID. In any other cases, please feel free to contact us too.