The salon turned my hair yellow?

i went to a local upscale full spa/salon, and had my hair bleached from medium brown to YELLOW. this is not what i wanted, i called the salon and let them know i wasn't happy, and they said they will need to tone my hair free of charge. what exactly does that mean, and will it work? and also...if i'm unhappy with my hair again, is it outrageous to ask them to keep working on it? thank youxo