Misleading information on new accounts

Last Friday my sister and I where shopping for winter clothes for my little girl, when we where approached to open up a new account.We where told that if we had opened up an account on that specific day, that we would qualify for a 50% discount on our first purchase. We where then told that I needed my I'D together with a 3 month bank statement to proceed. We struggled for a few hours to get the account opened as the accounts gentleman requested incorrect documents initially. During this entire process my sister and I kept asking 'how exactly does this 50% discount work?' and we where told numerous times that on activation of the acc that we would get 50% of our first purchase.So we went ahead and picked whatever I could for my little girl with the thought that I was going to get it at 50% discount.I eventually got to the till point with a bill of R2600 with the knowledge that I was going to pay half of that cash.The cashier then asked for a total of R2600, and said to me that the 50% discount was going to be given back to me in the form of a gift card to spend at their stores at a later stage.No one mentioned anything about the 50% being transferred to a gift card prior to that.