Dissatisfied customer

Bought Tekkies for school for my daughter on the 26th of December 2025, and today as its sports day I took them out and as she wore she complained that they are hurting her. I went back to the store to exchange them and get a bigger size, however I didn't get help. I firstly spoke to a shop assistant then he took me to the manager and he just gave me attitude. He said to me it's passed 30 days and there's nothing he can do and just gave me attitude. When I asked him for customer service number he said I should Google it myself as he doesn't have. I even have the receipt of everything that I bough for my daughter on that day. I'm very disappointed at the level of attitude a whole store manager can give a customer and its normal. I don't need money I just need shoes for my little one for sports