Poor Quality Product

I bought a pair of trainers for my daughter at Ackermans Mams Mall 3 months back and they are already damaged, I took them back yesterday for an exchange and was turned back because they are older than 3 months. The staff is not friendly and professional. The security at the door was with a friend having a chat while on duty. I asked them about quality policy because I mean I can't buy something with good quality to get damaged in 3 months, that's impossible. Really, I'm not happy with the service.