Spray for ford

RUST has appeared around the boot seal area on my 2004 Ford Territory TX AWD. It has a five-year paint warranty, but my Ford dealer says I must have been driving on dirt roads! After pointing out the rust is in areas where paint failed to reach, he grudgingly sent me to his preferred repairer for a quote, but I get the feeling Ford is trying to wash its hands of this problem by blaming the owner for neglect. How have I neglected to paint the damn car? I should have realised there were issues when I bought it. The left-hand doors had no paint on the bottoms and had to be repainted. The rear door has been out of alignment since day one and, despite many returns and resprays, it still is. Most frustrating is Ford's failure to fix problems correctly. I will never buy another Ford.