Exchanges issue without receipt

Good day On the 16th Dec 2020 I bought shoes for my boy at edgars east rand mall using store card. My challenge is I need to exchange the shoes as it is a small size and I have lost the receipt and still has a price tag on. Edgars has purchases records surely if they are helpful they will gladly assist me. My question is if they can't exchange the shoes where should I take them to? Meaning I have donated R229.95 to them? I find it not fair because I don't need money back I just need to exchange or credit back if they don't have the shoes on stock simple.