Tire Sidewall problems of the 1997 Chevrolet Lumina

I talked to "mark", cheswick-?, and he wanted odi to get this, we have now 3 big-o aspen p205-70r15 , on our 1997 chevy Lumina (car), the 4th blew out (just the outside sidewall,as if you cut a circle around it, caused car to drop, spin out and "totaled", car, cooper has what is left of tire and rim, he wants you all to get remaining "3", sidewall, has no steel, nothing, just rubber!!!!!!!!!, cooper said it was underinflated, lie I had just checked them prior to going on highway,also big-o, put on tire that is 8. 5 inchs wide, it is supposed to only be 6. 5, also it is the wl< wide tire.