I mistakenly sold some shoes on ebay as a size 7 instead of a size 6. The buyer obviously dosen't want them and I have offered a refund, in full plus the postage costs she paid me. However she has now emailed back saying that is not acceptable as she is out of pocket due to having to post them back to me. Should I cover the cost of her postage too? When things I have brought have been wrong then I have only been offered money back for the item itself, never the postage so I thought I was being fair. What do you think?