Dont honour warranty

Disgusting service from IStore Fourways. Bought a brand new Ipad which had a defect cable- I took it back to the store with receipt on the Monday literally 2 days after purchase and am being told that as its broken, the warranty doesnt hold. How the hell should I be liable for a manufacturing fault? Surely this warrants a replacement???? They want to charge a fortune for a broken cable which we did not break!!! So disappointed as these are not cheap!