Q.
Calls made on Viber appear on My regular call log… Is there a reason why and will it show up on the bill?
A.
We assume you're using an Android, right?
This is normal and expected behavior of the app. Even though the calls show up inside your regular call log, they will not be charged, since they were made over the internet.
In the future we will probably add a feature to separate both these logs.
Original disccusion can be found here


