Tire Blowout problems of the 1998 Nissan Altima

I was driving my 98 Nissan Altima through a residential neighborhood when the side wall of my douglas performance tire blew out dot #pjae1ylr0712. I put the donut on my car and took the tire back to walmart. In speaking to the sales person he said that the tires were not worn down enough to be considered a manufactures defect. So the had no warranty, these tires will only be 7 months old on may,9,2013. They refused to honor their warranty because I didn't buy their road hazard warranty at an additional $10 per tire. These tires were purchased on 9/9/12 I still have the original receipt they are 95/65r15.

While driving down freeway at 70 mph my left rear tire violently blew out. I gained control of the car and was able to make it over to shoulder. Tire was absolutely shredded to pieces. I have never seen anything like it. There was no previous evidence of excessive wear on the tire, and there were no foreign objects in road or in tire. I was barely able to maintain control when the tire exploded and as I crossed over lanes to the shoulder. This tire could have caused a serious accident and deaths. ( dot number: ).