I have a nasty waxy residue inmy hair I cant get out?

I used garnier fructis body booster root booster. Now I have this nasty waxy residue in my hair. I tried washing it llike 7 or 8 times. with 2 different shampoos, and even with dawn dish soap. Its still there. I even called the customer service , gey just told me it should be washing out.Help I don't know what to do.