why cant i hear anything during a call

[music freak2]

Hi.I have just got my samsung galaxy s7 edge which my brother bought in England.Now i live in Albania.Here is the problem,all the function which includes using the sim card work like mobile internet,messages but when it comes to phone calls i call a number,they answer but both sides cant hear a thing.Also online calls like What's up work.Only my voice phone calls dont.What should i do?

 

[louieloko]

Factory reset that's what I would do then see if the problem still exist and if it does warranty exchange