Holden Astra 2009: Should the brake rotors be replaced during the service?

When my partner took her 2009 Holden Astra in for its 80,000 km service she was told the brakes needed doing and that the front and rear rotors needed to be replaced. When she asked why the discs needed to be changed she was told that they were a throw away item and could not be machined. I recently drove the car and immediately noticed a pulse in the brake pedal as if the rotors were warped. My partner was charged for pads and rotors, but I don't believe they were changed. The car is booked in to have the brakes checked this week. If the rotors are warped, should she be paying again?