Zero Turn Mowers

I bought a RX4623 on July 19, 2013. I have a pulley that has lost its splines and I took it back to Lowe's for a warranty repair and the want to charge me $525 to replace the battery, blades, belt, spindle and pulley. I drove the mower into the store when dropping it off and used it the day before I took it to them. All I need is the pulley and maybe a spindle, is these items not covered by the manufacturers warranty? If not that's the most expensive 35 hour used mower ever.