Viber has multiple ways to displays contacts: the All Contacts and the Viber section (where only the contacts that use Viber will be displayed). To delete those contacts, simply switch to the All Contacts and locate them. Once they're located, long tap on each contact and choose Delete. Eventually, close Viber and then restart it and they should disappear from the list. Additionally, if the contacts appear as Viber-enabled, go to the Contacts section on your phone and delete them from there. Switch to Viber, then go to Contacts and press the menu/option button. Choose Refresh Contacts and they will disappear.
