FaFaFa Gold is designed to be in use for a single user account. This means that once signed in, your Facebook account will be locked into the device. The only way you can successfully log out of the application is to do a full Factory Reset on your iOS device.
Reset your device
Warning: Resetting your device will delete all content and settings all data from your device, including songs, videos, contacts, photos, calendar information, and anything else. All device settings are restored to their factory condition.
Before attempting a device reset, please follow this link to find out how to back up all of your iPhone or iPad.
For advanced users, please click here to learn how to keep track of the backups associated with your account.
Follow these steps to proceed with the reset:
1. To remove all settings and information from your device, tap Settings > General > Reset > Erase All Content and Settings.
2. If you can't erase your device, restore the device using iTunes.
Restoring your device will return your old game account. If you wish to do a factory reset and restore your device you will have to create another backup of your old iOS, this time via using iCloud.
(Settings > iCloud > Storage & Backup > Manage Storage).
From the options on the next screen, choose which and app data you want to back up exactly. Then hit "Back Up Now".