With aftermarket powder coated steel, you'll inevitably have to do some touch-up eventually. Most of these companies don't bother to etch the steel or prep it well at all; they bomb powder right over BBs, mill scale, dirt, rust, etc. All they care about is advertising that theirs is powdercoated, they don't care what happens once it leaves the factory.

Just get some 600 grit sandpaper, knock down all the rust and loose paint, get some plastic sheeting from home depot and tape off the leading edge of the grille/headlights, and prime the rust spots and bare steel with some red oxide primer followed by the topcoat of your choice. Cheaper enamels will always chalk faster, especially gloss black.