Stupid policy

My mom bought my children pyjamas and slippers from Ackermans on Sat. Upon trying it the one son’s slippers didn’t fit. My son and I went back to Ackermans today to swap it for a bigger size and was informed that 8-9 is their biggest size. We requested a refund since we’re unable to return the shoes and the staff at Ackermans Irene Mall insisted we have the original card that purchased it. How is that possible? What if my mom lived in CT and has gone back home? They refused to give us cash to buy it from PnP instead. How is it our problem that you don’t cater for big sizes? Not on the women’s shoes either. Now we have lost the money because we won’t be able to get the original card. Even though we had the original till slip.