It has been a while since I have been hit on Viber in particular but just now I got this call on my phone and from looking at the number knew it was a dodgy one, But these scams will never go away but this is one you can add to your block list and prevent it regardless and pass it on to family and friends. Prevention is not a bad thing and we can all help on this.
The call is originating in Mauritania and has several threads on the web about it. Here is the offending number here +22222304969.
TELLOWS have reports
Phone numbers.ie also have it reported on their database.