Tire Bubble problems of the 2000 Hyundai Tiburon

Bought bf goodrich tires from walmart. 195/55r 84v tract tires in June 2006. About 5 days ago I was checking my tire pressure and found a large blister/bubble on the side of the tire wall. Approximately 3 1/2 inches long oblong and about 3 inches width. I took my car to walmart in ravenna ohio 44266 where I bought the tires. They measured the tire width and checked the car miles and said they would order new tires. I also only got 24000 miles on the tire and they are 60,000 mile tires. At first the girl told me I would have to pay half the cost of the original tire to replace them. She also told me to call back in an hour or so when her manager came back from lunch, because she wasn't able to input the information for ordering, that she didn't know how to do it. When I called back she made all kinds of excuses. We cant order them because the manager didn't see the car and he has to check the miles and tread depth. I said I have a print out of that and you already did it, then she said well we may not be prorating the tires because we don't know if you kept up on the maintenance of the tires. I said what are you talking about. She said rotating the tires and keeping them in alignment. I hung up angry and am reporting them to you. I have a tire protection plan also that I purchased when I bought the tires. I showed all the paper work to the girl when I brought the car in for them to look at it. The mechanic is the one who checked the tire tread and the miles personally.