2000 CHEVROLET PICKUP Unknown Or Other Problems

I WAS DRIVING ON A GRAVEL ROAD WHEN MY SPARE TIRE UNDER MY 2000 Z71 CHEVROLET EXTENDED CAB PICKUP FELL FROM UNDER THE TRUCK. IT MADE THE REAR END OF MY TRUCK BOUNCE UP AS IT TURNED SIDEWAYS COMING UNDER THE BED OF THE TRUCK. I WAS PULLING A TWO WHEEL TRAILER AT THE TIME AND THE TIRE WENT UNDER THE TRAILER. I LOOKED IN MY REAR VIEW MIRROR WHEN I FELT THE TRUCK BOUNCE UP AND SAW THE TRAILER AS IT HIT THE TIRE. THE TRAILER BOUNCED ABOUT THREE TO FOUR FEET IN THE AIR AS IT RAN OVER THE TUMBLING TIRE. A CAR BEHIND ME ALMOST HAD AN ACCIDENT DODGING THE TIRE AS IT FLEW UP IN THE AIR AND LANDED IN THE DITCH. I TOLD THE CHEVY DEALERSHIP ABOUT THE ACCIDENT. THEY SAID THE CABLE HOLDING THE SPARE TIRE UNDER THE TRUCK HAD BROKEN AND IT WASN'T...