Call corporate. Do it in their presence. THey love that. Then buy the phone price matched, open it on the spot, and return it. Say you need another color. They will love that more.
They sell open box at 10% discount FYI
I've yet to see Best Buy do open box on phones, let alone iPhones. When I worked at Best buy for returns of cell phones, they were sent back to the manufacturer instead of back to the floor.