general problems of the 2005 Ford Five Hundred

Continental tires (215/60/17), chunks of the tire are coming off. Contacted manufacturer about issue, did not seem to be concerned about the issue (jose). Ford also was contacted about the issue and they too did not seem concerned, however both parties acknowledge that there is something wrong with the tires. A common question of both was, do I drive on gravel roads. I told them I did not, however Ford dealer said that there was shell and small gravel on underside of car. There have been roads replace in the area that I have driven on. Bottom line. I now have concerns about the tire safety on my car and both Ford and continental will replace them for a cost, but both refuse to acknowledge a tire "issue" at this time. Will someone have to die before something is done. I at one time owned a Ford explorer and went though those "issues". Have there been any other complaints about the tires on the Ford 500 or continental tires? could someone look into this issue and assist me. Thank you for your assistance.