Why Do Some of my Inbound VoIP Calls End up on Viber?

If your application has the Viber-In Calls feature enabled, you may receive inbound calls via Viber. This feature allows users to make incoming calls with Viber when possible.

If, for some reason, you don’t want to receive calls on Viber, it is easy to disable Viber-In Calls:

Go to Settings > Calls and Messages in your application.
Click the Viber-In Calls toggle to disable it.