And this is why you MUST intermix the cans before you shoot. In this case the colors are SOOOO far off you wouldn't want to intermix them as you would have a completely different color than you wanted! If you had opened both cans to intermix you would have seen it and corrected it. For this reason I seriously doubt the paint store is going to do anything but give you more paint, not the catalyst or anything else. ALWAYS intermix the cans, ALWAYS. A white is very touchy, just a drip more of a toner can give you a slightly different color you ALWAYS want to intermix.
Thank goodness this is all on the inside, don't sweat it. Get the correct color and repaint the areas that are wrong and get on with life. But be
SURE you have enough to finish the job and if it comes in two cans..........intermix them. Here is a "Basics of Basics" on the subject of painting the car in pieces.
http://www.autobodystore.com/ms27.shtml
Brian