ION 9N Very light blonde.

An employee at my store recommended that color to a customer who had like a 10V base. She came back to the store upset, with the hair dye applied, still. Saying how the girl that was there with us earlier recommended her that hair dye. When I looked at the glob of hair dye applied to her hair, it looked slightly brownish but at the same time like a 7N. I had asked her if she checked the tube to make sure it was the same color as seen on the box. Because we’ve had customers that had switched out tubes from other hair dyed before. I had also told her that maybe once she rinses it off it’ll look lighter. Then she told me “no it’s not gonna lighten look at how dark this is, it looks nothing like the display.” I told her that she should rinse that dye off as soon as she gets home because she shouldn’t be walking around with a hair dye applied for so long on her head. She ended up taking a lighter shade of hair dye with a 30 volume. Has anyone ever dyed their hair using the 9N from ion? Or maybe fill me in on some details on why it might’ve turned that color when she applied it?