Take it to the Microsoft Store, the people there rock. I've always had great service, they let me trade in an RT surface for my Pro and they gave me to full price of the RT.
If I were MS, I would advertise that I take all Apple products on trade for all MS WP & Win products. Can you imagine the amount of press this kind of ad would bring? I think it would help sell Lumia and Surface products to those iSheep that are on the fence.