No delivery of order, refund refused

Hi everyone, I ordered stationery from them on the 19th of November, I paid for express shipping because I needed the stuff by the Saturday. After they confirmed my order and the shipping date, I did not receive my stationery as agreed on Thursday. When I followed up the Friday, they said I have to pay extra because my artwork was not right, it was high res saved in PDF as they requested. I asked for a refund since the stationery was for an event and I wouldn't get it in time anyway and.....nothing. To this day, I have not received a refund and when I contact them I get a flimsy response. They offered me a credit for future printing and I asked them to go ahead and print the stuff but told them I would not be paying extra since I paid for express shipping for things I did not get. Again, no response. Save yourself the trouble and use your local printers.