Tire Sidewall problems of the 2008 Mercedes Benz E350

While traveling at ordinary speed on even interstate surface (I-64) east bound the rear right tire of my mb E350w4 blewout. I was able stabilize the car and exit the highway as I was just then in front of a an exit. My tires had been recently inspected during a regular service of my car. There is no reason or event which could have caused the sudden tire failure. I have filed a complaint with continental tire customer service, but the company has failed to acknowledge that their product may have manufacturing issues. Now I have observed a blemish developing on the sidewall of another tire. The dealer has suggested that "we watched it" for a time and see what happens. My tires are continental, contiprocontact, 245/40 r18 93v, ms radial. Replacing the tire cost me some $350 sand could have cost me my life or very serious injury had I been traveling at higher speed or ir the front tire had failed rather than the rear. I firmly believe these tires pose an immediate threat to public safety.