Tire Bulge problems of the 2000 Dodge Ram 1500

Had vehicle inspected prior to getting front end alignment at tire discounters. They noticed a bulge on the inside sidewall. Kelly tire less than 30 days old. They tried to tell me that the bulge was from someone hitting a pot hole to hard. I think that it is a defective tire and they just did not want to take care of it. I was told that all the tire that were purchased at a goodyear retailer were 2nds with known defects. I contacted a goodyear retailer where I live and they refuse to replace them unless I was the original purchaser with the receipt.