The Buyer-Seller Messaging Service enables you to communicate with buyers via Seller Central or your email account. You can contact buyers to complete orders or to respond to customer service questions.
If you don’t receive a response or your message is blocked, please keep in mind that buyers can opt out of receiving unsolicited messages.
If your message is critical to completing the buyer’s order, you can ensure it is sent by following the instructions mentioned as Buyer-Seller Messages.
For more details see, Buyer-Seller Messages(Login required)