Removing Henna from Hair

Hi Guys
i am new here and facing a serious problem.
actually i am dying my hair from black henna from 1 year and now i am fed up with black and trying to dye my hair but no color is coming on the hair.
in fact the new dye only show hair dye color on white hairs that are just near the roots and no color on the rest of them.
now i went to the parlor last weekend and ask her to cut down the hair color and ask for the streaking. she tried twice but no color cut is made on the black hair. and the golden color is on the root which is really looking nasty.

i have spent so much money and still got no plan and not good appearance. now i dont want any experiment looking for some genuine solution. and if someone have gone through this trouble and know what to do exactly please assist me.