That's a pretty poor match, but assuming the sprayer has done it according to the spec. you've provided them, I'm not sure you've got much comeback unfortunately.
If you'd left the car (or at least the other mirror cover) with them and asked them to match it then you could probably reject it, but if you've just given them the paint code then they've done as you asked.
It's the OP's car, not yours, so quite frankly your opinion on the matter is irrelevant.