Pathetic Service

My wife purchased 2 T-Shirts for me from the Table Bay Mall (Cape Town) branch of Truworths Man on the 23/10/2022. The receipts for the purchases were thrown away by our housekeeper. Unfortunately, these were 2 small, and when I tried to exchange them ( both T-Shirts had the price tags attached) the cashier refused to as she insisted on a receipt. I asked her to if I could provide a bank statement as proof of purchase, and I mentioned to her my wife was on the loyalty programme, but she still refused - even after consulting with the store manager. How can a bank statement, proving that the purchase was made, not be sufficient? Why cant Truworths obtain the details from the loyalty programme records ??