Blocked on Viber? How to tell:
If you are *desperate* to know if you have been blocked on Viber, then send a support email to Viber at: http://support.viber.com/customer/portal/emails/new and use the number of the person you want to find information about.
By pretending to be the person in question, you can ask them why you aren't able to contact another person (your actual profile).
They will investigate, and if you are blocked, they'll tell you so!