Wizard of Math Questions, email us at support@wizardofmath.com . Unfortunately, due to the speed of our automated systems, once an order is placed, we are unable to cancel or modify the order. You can return the item for a full refund (less shipping) if you inform us same business day that you wish to cancel your order. Please review our return policy below for all the details. Returns Policy: To be eligible for a return (except in the case of a defective product) the product must be returned unopened and/or complete with the original packaging and must be in resaleable condition. Products returned which are not in original or unopened condition (except defective products ) or products returned beyond 30 days of original receipt by the purchaser or, products returned unaccompanied by a valid RA number will not be eligible for a refund. Once an item is received back in acceptable condition with a valid RA number, we will issue a refund minus a 15% restocking fee. In addition, we cannot refund your initial shipping charge nor can we reimburse you for a return unless the return is due to our shipping error or in the case of defective products. All returns with a valid RA number must be sent to: Wizard Of Math 2575 Schillinger Road Semmes, AL 36575