Pep Stores review: Service

My mom bought my baby baby grows at pep in Kuils River Shopright Mall. About a week later she gave it to me and before even fitting it on my baby I saw it was the wrong size. Because its more than a week later my mom no longer has the receipt. Pep stores refuses to exchange it for the same item just a bigger size without the receipt. The items even still has the tags on them. The cashier did not even greet me and when I told her I dont have the receipt she just threw the bag back on the counter without looking in it or at me turning her towards the next customer saying we dont exchange without receipt and just went on with the next customer. Every cashier I have dealt with at a pep thus far has a bad attitude. They do not know how to manage a customer in a professional manner. I have never had this problem at another store hence me not shopping at pep. This is the second time this happens to me at a pep store. I want to know since when does pep not exchange without a receipt if items are still tagged? when did this new rule come into effect and why?