My nephew bought a school bag at Kempton pack for his little brother but then we had to go to an exchange it here at Hammanskraal

My nephew bought a school bag at Kempton pack for his little brother but then we had to go to an exchange it here at Hammanskraal. We had a proof of purchase as it was bought with an account and we even went to the store to ask if it's possible for us to exchange it and 2 of the employee said that it's possible the account hold should go to the other store they will communicate telephonically as the other person will be at sportscene Jubilee grossing. But when we got to the store they refused to help us saying that the account holder should be here with us but yesterday they didn't said so.the was no manager in the store. We spoke to Second incharger. He refused to give us the head office contact number. Non of the staff have name tags and the child was suppose to go to school yesterday, he couldn't. We were in the store yesterday and today without any help. So pls help us 🙏thank you