In this case, you might experience some error with your application. It's possible that you might have some leftover data in the application's cache that is alternating your information about contacts. To fix this, go to Menu of your device > Settings > Applications > Manage application > All, tap on Viber and choose Clear Data and Clear Cache. After you did this, open Viber. If you still experience issues with the application, try to update its version to the latest one. Also, contact the developer on the following website if you still can't fix the error.
