Refund

I bought shoes for my kids on the 20th April 2024 Truworths Wonderboom the shows were small and I have went there yesterday to return or get an exchange and I was informed they can’t assist because I lost my receipt. I used my debit card which is proof and the shoes still has the tag from the store. Why can’t exchange or get my money back with the proof I have. We living in the 4th revolution why don’t they even have a digital receipt in this time we are living in ,I need my money back