Rattling inside my left earcup

G'day mates, Recentally i got blackshark v2pro for christmas and after couple of days i noticed that the left earcup had lose parts or something as there was rattling sound coming from it every time i moved my head. I am a student and i have to have my earphones on all day. At first i thought that i would get used to it, but here i am almost 2 months later, my ear hurts uncontrollably after just a hour bcs i move my head so much. Is there any way to resolve this or do i have to get a refund?