Please contact your buyer directly to let them know that this has happened. You will then need to issue them with a full refund via PayPal ASAP (ticket, delivery costs and buyer's fees). Once you have done so, please contact our support team with your order reference number so that we can update the status of the order. 

In this case, we cannot refund the fees as you have breached our terms and conditions by not removing the tickets from Twickets when they were no longer available for sale.