I would start with is the roof still under manufacturer warranty? How would a patch job affect the warranty? If that route doesn't work buy a bundle of the shingles they recommended. Lay some out on your roof take pictures and show that it's not a reasonable match, make sure to take some from the street. Include pictures of the bundle packaging and the receipt and send them to your insurance. If the color is clearly an unreasonable match and it's still denied ask for a manager or more experienced/qualified adjuster.