The supplied Lightning USB Cable has given me unique problems. Not long after using, the white plastic coating began tearing-off thus exposing the live wires within. I brought the cable to my local Apple Store for a replacement but they refused saying that I damaged the cable. They wanted me to buy a new cable. I thought it was guaranteed for 1 year and how could I have caused damage to make the white insulation peel-off? Do any others have problems with the cable? What action should I take?