I got my hair from dyed black to dark brown but I want it a lighter brown, I don`t know what to do, I don't want to dye it, in case it turns out darker, what is the best anti-fade shampoo to use and how long will it take to get it right

You can mix some baking soda and shampoo. It is supposed to help fade out colour. Also, there are clarifying shampoos out there in most beauty shops, pantene do one in a clear plastic bottle. The more you wash your hair, the more the colour fades. These shampoo tend to dry out the hair so be sure to use a conditioner.