You need to edit or end your listing (also email the current bidder to explain why you are cancelling their bid and relisting) if you don't have the box, you state in "item specifics that it has both the box and the earphones then later on say it doesn't.

You could easily lose a case for "item not as described" for that and lose you money and the phone........................

Edit to say.       At the very least you should email the current bidder who bid before the revision pointing out the lack of box.