You are free to cancel your order at any moment you choose to. The complete order amount will then be refunded to your account. After 5-7 days the money will appear on your bank account.
You also have 14 days to cancel the order, after you have received the item. The days starts to count the day the item is delivered to you. It requires that the item is not used and still is in the packaging. The customer have to pay for the return shipment and is responsible for the shipment. That is why recommend insurance on return shipments.
For pre-orders the same rules apply. You can cancel at any time, including 14 days after delivery, but have to pay for return shipment.