Apparently they don't have the courtesy to contact you to let you know the item that was requested was no longer available. I would have totally settled for something in a different color, there were maybe 7 or 8 to choose from, or maybe a different item in its place. Nope, not one notice about it. When I called to complain they told me I would have to pay for shipping again if I wanted to make a new order. Apparently I should have known that I could call ahead to order my exchange before sending out my package, I wish I'd known that.
EDIT: Exchanges have free shipping (if what you ask for in exchange is in stock, otherwise they just refund your money and end the order there) - Old Navy gives you prepaid return slips for UPS - I should have clarified that.