Phone calls seems to be from viber while they are not! It strange to say but it happens to me often when people call me from italy only(This probably might happen from other countries as well). They call me in their cell phone while at my smartphone it comes as a viber call.
So I open the viber calling and continue to talk to them, and I ask if they are calling me from viber but they say: - No I am just using simple call option.

I am using samsung galaxy j5 2016

Does anybody have any idea why this might happen ?
Should I check something into my phone or it has to be due to their payment plan or something ?
I think I found the solution in viber app. Going to settings > calls and messages > viber in calls. It was checked so I unchecked it because it says: - Receive regular incoming calls with viber when possible