Tire Tread/belt problems of the 1998 Chevrolet Astro

Mastercraft "sensys" tires. 215/70r15. A complete set of four tires had the treads separate. Resulting in a potentially very dangerous situation. When a complaint was filed with the wholesale supplier williams tire (of 3995 dorchester road, charleston, SC. 843-554-0700 fax=5541334) they stated they have not had any other complaints---but they confused me with someone else who had also complained---leading me to realize that there have been other complaints about this matter. I feel that my 4 tires cannot be the only ones. There must be more of these dangerous tires on the road.