You most likely got some kind of email about your order. If you re-read the email, check that it says black for sure. If it does, call apple again, tell them (in a calm voice) that the return and re-shipping will inconvenience you a lot, and that you currently have no other phone as you sold your old one to help pay for this one. They should have no trouble sending you a black one and you send them the white one when you get the black one.