Refuse to help a toy exchange that was a gift without receipt.

I am a regular customer at pick n pay hyper in centurion. My son received a toy from a friend for his birthday and my son already has the exact same toy, they told us it was bought at pick n pay hyper in centurion lifestyle and don't have a slip for it as they bought it and through away the slip on their way to spur for the party. They also dont use a smart shopper card. When I went today 11 may to go and exchange for one he does not have the manager just said no its not going to happen and I must provide a slip. So now I will be thinking twice before I make any future purchases from this pick n pay just because of the lack of customer service and they even scanned it and showed what it was with the price but still refused. This one refusal to do an exchange, not a return might have just been the last time pick n pay sees me or my family, going to checkers from now on. I have never ever been rejected for an exchange for a gift someone got me if it was needed without a slip, just to add one detail as well, I saw someone in the same pick n pay buy some items for a begger in store and he went straight to the refunds area without a slip and got cash. So how the F is that fair?