Preston Hyundai Did not repair warranty issue Boardman Ohio

I have had my 2010 Hyundai Elantra at Preston Hyundai because the brakes were hanging up. The car only had 25,000 miles on it. The repair order shows that they replaced both rear brake assemblies. I took it in again after about 5,000 miles because the brakes were still hanging up. They wanted to charge me for cleaning the brake assemblies. I told them I would take it to another dealer.

The car now has 31,000 miles on it and I took it to another Hyundai dealer. The dealer guaranteed me that ALL of the brake assemblies are the original factory brake parts from 2010. Isn't this called fraud? 

The dealer told me that all of the brake rotors and shoes need replaced. He said the shoes are rusted in the calipers. The cost will be almost $800.00 to do the work. 

The brake pedal is now going almost to the floor to stop. I am not going to pay for something that should have been covered under warranty. I told my wife that if I get involved in a bad accident to get an attorney and go after Preston and Hyundai!!