Does not action my refund

I placed an order in February 2025. They were not able to deliver the part according to the advert. I said fine, they can send me a refund. They have a lack of communication problem because I have to continue to try follow up about this- always unsuccessfully. I eventually got through and they said that they would action my refund. This has not happened. We are now in July 2025 and I still have not received my refund.