2006 VOLVO XC70 Wheels Problems

MILEAGE ON THIS VEHICLE WAS 115K WHEN THIS HAPPENED: MY WIFE STARTED TO BACK THE CAR STRAIGHT OUT OF OUR DRIVEWAY (FROM A STOPPED POSITION, IN REVERSE GEAR) WHEN SHE HEARD A LOUD BANG WHICH CAME FROM THE DRIVERS SIDE FRONT OF THE VEHICLE. SHE STOPPED THE VEHICLE AND PLACED IT IN PARK. AFTER REMOVING THE LEFT FRONT WHEEL, I DISCOVERED THAT THE SUSPENSION COIL (OR SPRING) AS PART OF THE MACPHERSON STRUT ASSEMBLY, HAD SNAPPED IN TWO AT THE LOWER END. THE BROKEN OFF PART OF THE SPRING WAS SITTING ON THE LOWER CONTROL ARM, WHILE THE OTHER PART WAS STILL SURROUNDING THE STRUT. THAT PART OF THE SPRING WAS RESPONSIBLE FOR SLASHING THE TIRE WHEN IT FAILED. WE WERE THANKFUL THAT THIS HAPPENED ON OUR DRIVEWAY AND NOT GOING DOWN THE HIGHWAY AT A HIGH RATE OF SPEED. BUT WE WERE ALSO ASTOUNDED THAT SUCH A CATASTROPHIC FAILURE...