JagOwner

I recently bought a 2016 Jaguar XF from a dealer. He gave me two sets of keys, one a Jaguar branded key, the other, described as the spare key, was passed to me in a sealed manilla envelope. When I got home, about 60 miles away, and took the spare key out I found it doesn't work. Dealer claims it came with the car and accepts neither he or his staff checked the key to see if it worked but looks to belong to a BMW. Views?