Truworths unhelpful with use of Mall Gift Card

I went to Cresta shopping mall because I was gifted with a shopping voucher for the mall, to the value of R1000. I first spent at Jet for R310. I then went to Truworths to use the remaining balance. The item I was buying was R900. I thought they would take the remaining R690 from the Gift card and the balance I could swipe with my Cheque card. I was told their system does not allow two card swipes, I needed cash. I left everything and went OUT THE SHOP to withdraw cash. I came back. Now when they tried to swipe the Gift card, it kept on declining, a number of times, almost disputing the balance left. Again a system faux par, they can't check the balance inside Truworths, I now left the store for the second time to go check the balance at the Info Desk. Got it. Went back to Truworths. I gave them balance slip, they tried to swipe the Gift card again, still would not go through. Called Manager. Failed. I asked if there was no way to override the system. He said NO! I was left helpless, with no one coming up with a solution or trying to figure another way out. I frustratingly took my Gift card back and left the shop, with the intended goods not purchased. I believe both cashier and manager did not try the least bit to assist, especially after going in and out of the store twice to meet them halfway on their poor systems. I will not drive again to Cresta to repeat this transaction. I want the item I had intended to buy as I believe it should not be my problem that the Truworths speed point could not accept my Cresta Gift Card. I can't have a Cresta Gift card and NOT be able to use at any of the stores at Cresta!