Paint question. need help!!

40th_z

So I dropped off a bumper at a local shop, they've tried 2x and both times they cant seem to be even close to the 40th color. I follow some of the fellow 40th builds on the forum and most of you guys seem to have zero issues repainting/matching body kits, lips, rear spats, etc. so i was wondering if there are any tips your paint shop might share? The shop keeps telling me they want to blend it with fenders but I dont want to mess with original color, they claim bumper will never be a perfect match which i think is bs. I'm looking for a new shop at the moment but no luck so far. I'd appreciate any feedback.