affiliatedbatteries.co.za didn't supply part, refusing to give me a refund johannesburg gauteng

I am in Botswana and I purchased a battery from affiliatdbatteries.co.za on their online platform. I paid with my card. They told me that they are unable to supply the battery and they will refund me. I placed the order on 28 March 2023 and still I have not received my refund despite numerous requests for them to do so. They claim they made a payment and that it is lost within the banking system which may be true because they did not use the swift code I provided and may have sent the money to a local recipient instead of me in Botswana. They have now started to ignore my messages and screen my calls. The contact number is +27 83 437 2249 Please assist me.