The Nokia Spain shop is a complete disaster: with luck you can reach one competent person, that guides you through the RMA process. I understand that the online shops are outsourced so this is not a direct responsability of Nokia.

In my case: I must put the N900 with ALL the gifts (BT headset and USB battery) in a box, they send to my email a sticker that I must stick to the box. Take that box to Correos (the national postal service in Spain) and wait at least THREE weeks to get the new N900.

Other companies, send an UPS courier to your door to get the box and send the replacement equipment (computer, batery, etc.) in the exact moment that the box is received back.