HOw long do u wait to complain about color

I get my hair colored and cut at the same salon .. about every 8 weeks... I normally get two colors a light red and blonde done with foils.. this time she put in another red.. copper and blonde and the light red.. I am more red than blonde and the copper is too red.... She said it would fade into blonde...........after washings... what is the best way to make it fade or shall i go back and have her fix? I want what is best for my hair... is too red... I have never gone back and complained does it happen often and what do hair dressers think of it? are they offended?