Repair about iPhone 4S headset and microphone

I bought iPhone 4S when I am in the trip in Swizerland, but I did not check it at that time by using. Then after few month using, the problem happens that the headset and mirophone don´t work when someone is calling me or I call others. So I would like to repair my phone any way. But now I stay in Norway, I would like to ask what is the best choice to fix the problem, go to Swizerland Zurich Apple Store to repair or I can mail my phone to them, then get the phone back via mail as well? And if I can mail the phone, how can I contact with the people there, because there are not so useful information on Swizerland apple website.