Wheel Related Problems of the 2007 Ford E-450

Wheel problem

While on a trip and while returning home the r/r inside tire tread separated causing the vehicle to sway. I was traveling on highway 231, a 4 lane highway,. I was traveling 65mph at the time of the tire failure. I was able to pull into the florida welcome center located on the florida alabama line. I had to call someone out to change the tire. After returning home to panama city, florida I took the vehicle and tire back to pep boys to have it replaced. I advised the service writer that I hade purchased road hazard insurance when I purchased the tires and advised him as to what happened and he advised me that tire separation was not a road hazard and that I would have to pay 50. 00 dollars to have the tire replaced. The tires I bought for my motor home were definity dakota h/t lt 225 75r 16. The service writer advised me that they no longer sold this tire and replaced it with a cooper tire. They put the tire that was on the r/r outside at the time of the inside tire failure on the inside of the wheel and put the new tire on the outside. Now I am having problems with the r/r inside tire not holding air. I feel that these tires are not safe to use on another trip. The service writer did not look to concerned about the problem.