I previously had bright blonde hair, although after my routine trip to the hairdressers I had a different toner which was grey. The grey lasted no more than 2 washes and I'm left with an awful brassy brown colour. Will my hair go back to the bright blonde and how do I get it back to it fast?!
Go back to the salon. It kind of sounds like they messed up and used the wrong toner. I can't see why it would be a brassy brown colour from bright blonde.
Geez! I agree with Janine, that sounds like the salon messed something up, I would make sure when you go back to talk to the manager so they can fix it, or get your money back.