Paint problems of the 2006 Kia Motor Spectra

Vehicle was purchased brand new from dealer in 2/06, brought regularly to dealer for any and all warranty/maintenance work. This year vehicle was brought to dealer because at times when the brake were applied the vehicle lurched forward and sounded as if the gas was being applied at the same time. Dealer assured this was the abs kicking in , and all was well. The second time this occurred the vehicle in front of ours was hit, and accident report was filed. There was no property damage. The vehicle was again returned to the dealer because the paint was coming off the car below both rear doors on both sides, we were told this was due to salt and sand. However there was no other part of the vehicle effected, and we saw that on the 2007 Spectra there has been a guard added to ensure that this did not occur on the 2007 Spectra. However we were told that the warranty did not apply because we lived in a salt and sand state. Therefore, even though the car was washed weekly, in less than a year ,it will simply continue to rust and we have no recourse.