if buyer chooses to hit the buy button without getting a price for delivery from the seller the buyer hasnt a leg to stand on, you'd have been in your rights to add the delivery cost to the invoice and when the complaint came, tell them thats the cost ebd of story. if the refused to pay hit them with a non payer dispute. not your fault the buyer is/was a dope. any feedback would be removed i believe as unwarrented.