How can I get my hair back from dyed black/dark brown to my natural light sandy brown?

I have been dying my hair to a while now and want to go back to my natural light sandy brown colour from black/dark brown. I don't want to bleach and growing it out would take sooooo long! And it would be half light half dark which would look funny. I used John Frieda foam colour in light brown to get it back to my natural colour so when it grows it won't show the colour differance but the dye didn't take at all! Are there any good dyes which would take to black hair :/ Would be a great help! x