Dunns Returns Horror

I ordered shoes from their online store on 26 November 2023. The order was delivered, however, two pairs were too small. I process an exchange and couriers collected the items and the return was confirmed on 5 December 2023. When I contacted them last week, I was told that refunds take 7-10 days after items were collected. I have not received any communication or refund up to this point and the last attempt at an email simply reiterated that the "Ticket was closed". No one has contacted me to follow up or provide clarity on the status of my refund. This has been the most unpleasant online shopping experience I have had.