Wrong size mixed with the right size

Early this month went to PEP in small str Joburg to buy shoes for my twin gals.... Girls size was packed with infants size 5....i got home I pecked their clothes they went to visit for the weekend.... When they got back their grandmother screemed at me that I'm very stupid how can I buy a bigger size just to make them look like fools.... Was so embarrassed and disappointed with PEP... I don't have a receipt anymore and the shoes already worn.... Mmmxx