I had this problem too. I called the internet shop I bought it from and they said if I could fix it myself for under 35euros I oculd do that and send the invoice to them for a full refund of that. So I bought a spare backcover from http://www.klc.fi/ for 15euros + 7euros shipment. Its out of stock though so I am still waiting for it..

EDIT; btw, Nokia Care didn't care at all about this. They turned me to the shop I bought it from for help.