Incredible connection negligence

I have recently purchased a Printer online from Incredible connection, payment went through and i was invoiced with the receipt saying that my order is packed and ready to be delivered. Six days later Incredible connection phones and says that there was a pricing mistake and are unable to send through my order . This is unacceptable and negligent on incredible connections side . I have paid for the item and received the invoice for this , so the item should be delivered as promised.