My refund dispute from SHEIN to ABSA bank

I bought from Shein online and then requested for a refund, and they are adamant that they gave me my refund and the problem is my bank, they even sent me proof of payment, I called the bank and no one was willing to help me, they take me back SHEIN but SHEIN says there’s a problem with the bank. I went to the bank and they weren’t willing to help me at all they kept saying there’s nothing they can do which makes no sense. SHEIN even suggested I dispute and they sent me a transaction number assuring me that they put the money into my account . (ABSA bank branch: Campus square, Aucklandpark)