Bill -
see here about removal , but why not start with talking to the jobber about some satisfaction? what exactly is wrong? rough surface, or patchy?
powder coating cosmetics are only as good as the metal below - it doesn't "fill" pitting or irregularities, so if the metal wasn't smooth to start, powder coating won't fix it, and the coating must be applied to clean bare metal, so you can't do any "body work" other than file and sandpaper work, no filler - if you gave them rust pitted parts, it's yer mistake

tho' they should have warned you
if the job is patchy, blotchy, thick and thin, tell them you want it done right or yer money back
and delux54 - DON'T YELL!! it's not polite - powder coating properly done is great, resists chipping and scratching
much better than paint and I've never seen any fade, tho I suppose some colors might, just like red paint usually doesn't hold up as long as other colors
Bill