2010 Volkswagen Touareg Tires & Wheels Problems

I PURCHASED A SET OF 4 NITTO MOTIVO'S FOR MY TOUAREG TDI IN SEPT 2013 AT WHICH TIME I HAD 60,000 MILES ON MY VEHICLE. TODAY, 6/17/14, @ 75, 000 MILES WITH 15,000 MILES ON THE MOTIVO'S, I NOTICED 2 DEFECTS IN 2 OF MY TIRES. THE LEFT REAR TIRE HAD A HUGE BULGE ON THE SIDEWALL...ABOUT 3" INCHES ACROSS AND 2" HIGH. THE RIGHT FRONT TIRE HAD THIS 2" X 2" CUT/GASH OR SOMETHING ON THE SIDEWALL. I IMMEDIATELY WENT TO DISCOUNT TIRE WHERE I BOUGHT THEM AND THEY SAID THESE ISSUES WERE PROBABLY THE RESULT OF DRIVING OVER POTHOLES AND THAT ALL 4 WILL NEED TO BE REPLACED SINCE I HAVE AN ALL-WHEEL DRIVE VEHICLE AND THAT THE BEST THEY CAN DO IS GIVE ME A TREAD WEAR BASED CREDIT ON A NEW SET IN THE AMOUNT OF AROUND $320. I PAID OVER $1000 FOR YOUR TIRES, WHICH WERE WARRANTED FOR 60,000 AND I ONLY GOT 15,000 OUT OF THEM. AND TO MAKE MATTERS WORSE, IT APPEARS THAT THE QUALITY OF THE SIDEWALL IS VERY POOR CAUSING THE DEFECTS I MENTIONED. I CONTACTED NITTO NUMEROUS TIMES AND THEY ADVISED THAT THEY DO NOT COVER "ROAD HAZARDS" WHICH THEY SAY CAUSED THE DEFECTS IN MY 2 TIRES. THEY ALSO ADVISED THAT SINCE MY TIRES WERE ONLY MEASURED AS HAVING BETWEEN 5/32 AND 6/32 OF TREAD WEAR, ESSENTIALLY 1/2 WORN OUT, THEY ONLY WARRANTY THEIR TIRES IF THEY ARE BETWEEN 1/32 AND 2/32...IE, TOTALLY WORN OUT, BEFORE THEY WOULD ISSUE A PRO-RATED CREDIT. THIS IS ABSURD!!! THE WARRANTY IS FOR 60,000 MILES...AFTER JUST 15,000 MILES, MY TIRES ARE HALFWAY WORN OUT! I SHOULD GET A CREDIT FOR 75% OF THE COST OF THE TIRES. I WOULD REALLY APPRECIATE YOUR CONSIDERATION IN HELPING ME TO RECEIVE CREDIT IN THE AMOUNT OF 75% ($750) OF THE $1000 I PAID FOR THESE TIRES, SINCE I ONLY HAVE 15, 000 MILES ON THEM AND THE WARRANTY IS FOR 60,000. *TR