The Manage Orders page

Here is some additional information:

• For seller-fulfilled orders, we provide you with a phone number that connects to the buyer during the fulfillment period. After delivery is complete, this phone number will no longer connect to the buyer. For more information, go to Prohibited seller activities and actions.
• You can also communicate with buyers through messages by clicking the Buyer’s name in their order.
• You must confirm shipment of the order with Amazon within 7 business days after the “ship by [date]”. Otherwise, Amazon will automatically cancel the order and you will not be paid, even if you shipped the order.
• When you confirm shipment for even one item in an order, we charge the buyer for the entire order.If the entire order is not confirmed, you will see the "Shipment is late" status in Manage Orders and a warning message on your seller account home page. These will appear even if you have refunded the remaining items in the order.