Tire Bubble problems of the 2006 Hyundai Sonata

The tires that I am filing a complaint are,general tires exclaims,225/50/zr17. These tires were purchased for my wife's car on 01/13/2011. Her car had 29,340 miles on it at the time they were installed by paramus Hyundai route4 east paramus,NJ. Her car at the present time has 47,990 miles on it,which means that she had only driven her car with these tires for 18,650 miles. I noticed that their was a weak spot "bubble" on the sidewall of the right rear tire. I had my wife take the car back to the dealer where we purchased the tires. The service manager informed her that three out of the four tires had weak spots and bubbles on the side walls of the tires and that general tires had discontinued the exclaims brand and that she must replace all four tires. I then notified general tires by email on 05/18/2013,and told them of the problem,and that I had registered the tires on their website and that they should have notified us of the problem. My wife could have been injured or even killed driving her car with three out of the four tires with "defects". They insisted that the weak spots and bubbles on the sidewalls were caused by "road hazards" without looking at them or checking them. I would agree if the defects were only two tires and both on the right side of the car but I do not agree when it entails three tires. Right front,left front,right rear. The person at general tire told me to take the car to a continental dealer and have them inspect the tires which I did. The person that looked at the tires did not put the car on a lift he walked outside and looked at the tires in a parking space. He said that he did not think it was a defect but a "design error" that caused the weak spots and bubbles and thats why the tires were discontinued. If that's the reason then general tires should have replaced the tires and notified us of the problem. The d. O. T. No. S ps403r7,s403ry3s10,s403ry3710, ps403ry, would not fit in space provided on form. Thank you.