@TJWINS -
We are continuously working to adapt Viber to more and more devices, and we hope to make your device fully compatible soon. When we have news, we'll let you know.
All -
If your contacts are not shown as Viber users (or you fail to call them, knowing they have the latest version of Viber on their WP8), please check out this link: http://helpme.viber.com/index.php?/Knowledgebase/Article/View/173/29/windows-phone-contact-list-is-not-showing-your-friends-as-viber-users
If the problem remains, or there is a different problem with Viber's functionality on your WP8, then we kindly ask that you take a minute and report the details of the problem to our support team using this direct link: Your ticket details (when you submit the ticket, please make sure to add the URL of our conversation). With this information, our development team will hopefully be able to find the source of the problem, and ultimately resolve it.
* For any other question/problem, we're right here to help.
Thanks in advance