I think you'll have to let the hairdresser wash out the color with shampoo. I had my first dye (after starting the cg method) couple of days ago and brought a shampoo & conditioner of my choice (SLS & cone free). When I came home I washed it again, with conditioner alone this time. It looks good still.

Also before dyeing, try not to have any products in your hair (like olive oil or ACV) - I'm just guessing here, but it might intertwine with the hair color. Just have it no-poo washed, pure and simple.

Modified CG (Oct, 2012.)
hair type:
2B/2C/, normal density, high porosity -.-
shampoo: Faith in Nature - Aloe Vera shampoo
: Faith in Nature - Aloe Vera conditioner
leave in: Alverde Styling gel White Tea & Lemongrass
: Burdock oil, Coconut oil