When you open the game for the first time, you will need a Facebook account or an email account to begin playing. Either of these will allow you to access the game.
All user Information, such as statistics and previous purchases, is directly associated with the account. For this reason, it is not possible to change an email address without losing all of the user’s history, including their achievements.
If you open the game and the email address shown is not yours, it is possible that your user information will not be displayed. We recommend that you close and reopen the game.
If an account was initially created with an email address, it can later be linked to Facebook. You can link an account to Facebook by entering Menu, then Settings, and then Account, where you can click on “sign in”. It is also possible to unlink your Facebook account, but to do so there must be an active email account associated to the game.