2000 TOYOTA 4RUNNER Tires Problems

I PURCHASED 4 YOKOHAMA GEOLANDER H/T-S ON A LOCAL REPAIR SHOP ON 02/2013. I TOOK MY VEHICLE IN FOR MY ANNUAL STATE SAFETY INSPECTION THIS YEAR ON 02/2015 I WAS TOLD AND IT WAS BROUGHT TO MY ATTENTION THAT MY TIRE ARE CRACKING BETWEEN THE INSIDE AND THE OUTSIDE TREADS. THIS TREAD SEPARATION CRACKING IS AN UNSAFE CONDITION. THE SHOP CONTACTED TIRE COMPANY THAT SUPPLIED THEM THE TIRE AND THEY SAID THEY WOULD ONLY CREDIT ME 35% OF THE ORIGINAL TIRE PRICE THEY WOULD BE REPLACED WITH ANOTHER YOKOHAMA TIRE. THESE TIRES ARE 2 YEARS OLD AND HAVE 30,000 MILES ON THEM. IT SEEMS I AM BEING PUT IN DANGER IF I DON'T HAVE THEM REPLACED AND SEEMS I AM GETTING RIPPED OFF IF I DO HAVE THEM REPLACED. *TR

TL* THE CONTACT OWNS A 2000 TOYOTA 4RUNNER EQUIPPED WITH SPECTOR ADVANTA SUV LT265/70/R16 TIRES. THE CONTACT STATED THAT THE VEHICLE WOULD VIBRATE WHILE DRIVING AT VARIOUS SPEEDS. WHILE THE VEHICLE WAS PARKED, THE CONTACT NOTICED THAT THERE WERE BLISTERS ON THE SIDEWALLS OF THE FRONT PASSENGER TIRE, EXPOSING THE WHITE MATERIAL INSIDE OF THE TREAD. IN ADDITION, THE TREAD ON THE REAR PASSENGER TIRE WAS RAISED AND THE CONTACT BELIEVED IT WAS DUE TO A BROKEN PIECE OF THE TREAD BELT. THE VEHICLE WAS NOT TAKEN TO HAVE THE FAILURE DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE TIRES WERE INSTALLED ON THE VEHICLE AT 140,000 MILES AND THE FAILURE MILEAGE WAS 159,000.