Get a new camera or new external mic ?

[D_halfrican]

I just got a new camera (Samsung nx30) when I went to edit the video there is this really bad hissing problem a little research later it's probably not gonna be fix by Samsung anytime soon. I still have time to return it to Amazon but i still like the camera should just return it and get a new one or should I invest in an external mic like a zoom recorder or something along those lines. I've tried fixing in post but that's a no go and any mics that plug into camera won't work either. Any advice would really help.