Tire Tread/belt problems of the 1996 Cadillac Eldorado

On November 22 2006, I brought four tires (sumitomo 225 40z18 su htrii 8) from sears at fairlane town center in dearborn michigan. I believe that the installer of the tire at sears was aware of the bubble. I would not have notice the bubble upon inspection of the vehicle at sears because it is dark in their service area. The bubble is hard to see even in sunlight. A few days (November 26 2006) later I noticed a bubble in the sidewall of my right front tire. It looked like a separation of the belt within the tire. I showed my friend. He agreed and told me to take it back to sears. I took the car back to sears on December 6 2006. The auto center service manager said that the bubble was caused by a pot hole. I told him that I had not hit anything. He was adamant about his position. He gave me a number for customer service. Customer service called that same manager and when customer service called me they had agreed with the manager and said they cannot help me. I called the manufacturer of the tire and left a message, a representative from the manufacturer contacted me, I explained the situation to the representative. He called the auto service manager and he (representative from the tire manufacturer) also agreed with the manager. The representative said, " the tire is not under a warranty and my problem is between you and sears". I researched the internet for complaints or problems with this type of tires. I read over 484 reviews on this tires and I found several similar or the same complaints about the same tire. I would like for a tire expert to look at my tire. There is something wrong with these tires and the manufacturer is refusing to admit that there is a problem with these tires.