family store? bull!!

about 5 weeks ago my daughter decided she wanted to buy an iTunes card with her pocketmoney. so I let her go into pick and pay, alone, to buy 1. 5 minutes later she comes back with a google play store card instead. I told her to go back and exchange it for an iTunes card. again she came back this time crying and told me the manager had shouted at her and wouldn't exchange it. so I went and saw the manager whom refused to exchange it and said that was policy and best they could do was keep it until somebody else came to buy one then they would sell them that one. ( don't the consumer laws allow for a customer to exchange a product that was incorrectly purchased?) so I again gave them my number and they promised to phone me. 2 weeks later nothing so I went back and they said the person responsible wasn't there so I gave them my number AGAIN and they promised to phone me..NOTHING! last week after waiting another 2 weeks I went back in again. the manager was extremely arrogant but once again I left my number and he promised me faithfully that the person responsible would call me the next day..once again a week later NOTHING!! really? over a R250 card for an 11 year old !!??