Samsung Galaxy S7 audio and microphone problems (brand new out of the box)

Описание: Samsung Galaxy S7 32GB SM-G930V (Marshmallow) audio and microphone problems (brand new out of the box)

Just bought this devise to replace my iPhone 5s.
Out of the box and in the first call I made they couldn’t hear me… I said ok… “it’s new I have to set it up” so I start looking around the settings. Sometime later it stopped doing it so I finished setting it up, putted my favorite apps, transferred all my photos and contacts from my iPhone (hopefully I created a total iTunes backup before resetting to factory defaults).
The problem is:
a) When I make a call I can’t here (no sound at all from the other side) unless I put it on “speaker mode”. At the same time and with the speaker mode off when I press the “extra volume” button it popups "Unable to use extra volume range while earphones are connected"…WITHOUT having the earphones CONNECTED.
b) To test it I used Samsung Voice Recorder. When I open the application, a popup at the bottom is saying: "External microphone will be used to record audio" …WITHOUT having the earphones connected again.
And when I press the record button another popup appears "Recording with external audio"…WITHOUT having the earphones connected again.
c) when I connect the earphone jack I listen & record nicely
d) Sometimes popups a “The location fd://24 cannot be played
It’s like always for some reason believes that the earphone jack is connected. Rarely works ok for some seconds but it stops pretty soon…

Anybody knows if it’s a software problem/bug that can be fixed or it’s hardware?

I don’t know… pretty disappointing, it’s too expensive to have this problems. Feels like I left macOS for windows 98 and loosing precious time again to google & fix, problems…