If your order includes a print textbook, there is a possibility the condition you selected (e.g. Used or New condition) is unavailable at the time we process your order. In order to serve you sooner, we will replace your textbook with the available condition, and your final order total will be higher or lower than your original estimated order total. If you are unhappy with this replacement, please contact us and we would be happy to assist you with a refund.