Tire Tread/belt problems of the 1999 Cadillac Catera

I have a 1998 and 1999 Cadillac Catera. Both cars have goodyear eagle rs-a tires. The 1999 had to have all four tires replaced with less than 25,000 miles. Goodyear paid for the front two because the camber specs given to Cadillac were incorrect. The back two were blamed on the delaer switching tires from another car. The 1998 had both its front tires replaced under the same program but the rear two seemed all right. They were until last night when one of the rear tires went flat. And the other rear tire could go flat at any time. All eight tires have exhibited the same excessive wear on the inside edge of the tread. The steel belts show and all rubber is gone on the edge. The remainder of the tire has tread comparable to your expectations for the milage of the car. Something is wrong either the camber or the tire itself. The flat last night occurred at 75 mph on I-12. A potentially dangerous situation.

Two of the four tires were showing tread separation. Metal was showing on inside of tires. All tires were showing wear and tear. (dot number: m6t4 tiresize: p225/55r16).