Poor customer service

My son visited the Incredible Connection store in N1 City on 19 June 2024, and after being advised by a salesperson bought a sd card for his device. Came home and after carefully opening the packaging noticed that the sd card was not correct. Went back to the store on 21 June with the original packaging, unused sd card and receipt and was told quite rudely by the store manager (Naasif Alexander) that they can only accept the return less a 15% handling fee. I disputed this handling fee and he gave a reason that he is unable to resell the card because the packaging is open. Why is it our problem that the salesperson gave us incorrect advice in the first instance. Secondly, the item is unused and packaging all intact so why is he reading the terms and conditioning in such a narrow perspective other than to suite his own predetermined outcome. Won't shop at Incredible Connection again as their customer service is wanting.