I sold a Marc Jacobs quilted stam bag for £600 just over a week ago (absolutely guaranteed authentic) buyer said they would leave feedback when they had it authenticated (so i told them to take several photos and post here or visit mypoupette) i hadn't heard anything so i messaged asking if they had confirmed the authentity , they said they went to Selfridges but they could not be sure as it was not purchased from them . Buyer has asked if they can now return the bag as his girlfriend won't carry the bag until it is authenticated, so i have again given several options to get the bag authenticated.... what do i do?