They have to fix it, really. Dont be afraid to go bad, you don't need to be aggresive, just show them your hair....

well first of all hugs for having had that done to your hair ,i know just how your feeling ,i had my hair all burnt and sinjed for my wedding day it was terrible,there is nothing worse
but yes dont get angry (or cry like i did lol) but go back and tell them to fix it or your going to call consumer affairs or something ?
good luck