Shein Refuses My Refund and Claims My Capitec Card Is Declining

I made my first purchase from Shein, and the experience has been very bad. I ordered several items, including books, a hot blanket, makeup items, and games, and requested a refund on Sunday night. Shein is now telling me that my card is declining, even though I have been using the same Capitec card without any problems. The explanation that my card is declining does not make sense, because I paid for items worth R851 on Shein just yesterday using this exact Capitec card, and the payment went through successfully. My card is working, and I use it for other payments as well, so the problem is clearly not with my bank card. I request that Shein immediately process my refund to my Capitec card without further excuses and provide a clear confirmation of the transaction. I also expect this issue to be resolved quickly, as this is my first time buying from Shein, and the experience so far has been very disappointing.