Tire Tread/belt problems of the 1999 Mazda Millenia

Tire size 215/50r17. Mounted on a Mazda, milleneum 1999. Both front tires had tread separation. Contacted dealer, and dealer was willing to pay back only 50% of tire cost. Dunlop sports 4000 tires.

The vehicle was purchased in March 29, 2000 with 3,636 miles on it. With less than 20k miles, the tread separated on the left front tire on Friday, December 22, 2000. On February 9, 2001, I took the vehicle in to be serviced, including a tire rotation and balance, 4-wheel alignment. When I went to pick up the car, the right front tire tread had separated and the technician had placed the spare on the vehicle and advised that I needed a new tire. When I told him it was the second tire in less than a year of ownership, he said I needed to contact the manufacturer. On Friday, August 10, 2001, I had a third of the original tires tread separate on the left front side just 10k miles after my alignment. No one seems to know what is causing the tires to wear excessively on the inside and separate. When I took the car in to replace that tire, the tire dealer informed me that the last of the original tires was wearing and very susceptible to the same type of tread separation. By the end of the day tomorrow, I will have spent over $600 to purchase new tires for a vehicle that has less than 31k miles on it. Please help! (tiresize: 215/50r17).