Well you know by the name of your company she's a complete wack job! That moron can request anything she wants its not her decision nor will PayPal act upon it. Especially if you have proof of shipment. Its not your fault by the USPS's if what you say is true. She's not granted any refund whatsoever if she decides to keep the merchandise. She's wanting free items for someone elses problems. If she's purchased from you before, like you said, she knew she'd get the items provided it wasnt just 1 other time. Dont bother warning the moron about blacklisting her, just blacklist her. How you run your company and who you decide you want to do business with is your business not anyone elses. You can make threats all you want, if you dont want to do business with someone thats your legal right. Once the item is delivered close the case, make sure her name address and information are kept in a database that if she tries to buy under another IP you'll know, refund her money and get rid of her.