I have a 16GB Gold 6S+ on the way tomorrow. And with 4k video and all 16GB Won't be enough. I also want a space grey 6S+ now. How would I go about exchanging it and getting a 64GB Space Grey 6S+ ? Do I send it back to Apple and give them a extra 100 dollars or what ? There is a 14 day return policy, but there won't be any more 6S+ available until Oct-Nov.