To contact a buyer about an existing order, click on the "Contact Buyer" button to the right of the order in question from the Members Area > Buying section:
HipStamp Buying: https://www.hipstamp.com/members/selling/sales
HipComic Buying: https://www.hipcomic.com/members/selling/sales
HipPostcard Buying: https://www.hippostcard.com/members/selling/sales
Once the buyer responds, we'll notify you via email that you have a new message, which you can view from the Messages section (Members Area > Messages section), and linked below:
HipStamp Messages: https://www.hipstamp.com/members/messaging/browse/filter/received
HipComic Messages: https://www.hipcomic.com/members/messaging/browse/filter/received
HipPostcard Messages: https://www.hippostcard.com/messaging/browse/filter/received