re #114-5750027-2645835

Customer wants to return item because one volume of the 28-volume set is missing I received the "return authorization" notice from Amazon and within 30 minutes tried to contact the buyer to offer a replacement of the missing volume. When I click on "send" for the buyer message I get a pop-up window that says "This is the final message that will be sent to the buyer. Please verify that your message is written in the buyer's language of preference: English". When I click the "send" button again that same pop-up appears. What am I doing wrong (or maybe the buyer already put the item in transit with RFS and in that case the buyer can no longer be contacted)? Ooops, I just now see when I try to contact buyer through the order page, at the very bottom, a pop-up says "Buyer has opted out of receiving non-critical messages" and the only option was to refund or provide replacement. I want to only provide a replacement on the missing volume. Can that be done? If I'd have to replace the whole set, then I would prefer to accept the turn.