When you order the phone, they pre-authorize your card for the amount (to make sure it will go through), and the pre-authorization comes off in a few days.
Only when the phone actually ships will you be charged.
Its very common practice. Check your online statement after eating at a restaurant, they usually pre-auth a higher amount than your bill to account for potential tip. It comes off in a few days, then the real charge shows up a few days later.