Brake Disc Pads problems of the 2013 Kia Motor Optima

I had my brake pads and rotors replaced in November 2017. The service dept at the dealership indicated, they would not pass inspection and were beyond salvaging. I had them replaced. In April, I went back to the dealer for routine service, including an oil change. I had complained of vibration in the brake pedal and was advised it was normal. On August 3rd I had another oil change and requested the brakes be looked at, as the vibration was at a point of concern. The serv dept indicated the front rotors were warped and needed replacing, less than a year later, and less than 4000 miles later. I was upset and they were able to charge me 1/2 the cost. That evening I drove and found the vibration to be exactly as before the replacement. I went to the service dept, yet again on August 8. They indicated the vibration was from the rear and those rotors needed to be replaced. There are only 42000 miles on the car. I drive less than 3 miles round trip each day. I discovered that they were never road testing the car, just looking at the brakes/rotors and replacing. They are either putting warped rotors on the vehicle and/or lying about replacing them. I could have saved time and money had the work been completed right , the first time.