HELP! Blue highlights

I had brown hair with blonde highlights and decided to just tone it a bit down.
Hair coloring disasters of my teenage years made me vow to never touch haircolor on my own again, so I went to a SALON.
The "Pro" was obviously completely incompetent.
As I found out later, she put a neutral brown (which according to the company's webpage completely eliminates all red and golden tones) over it
I ended up with way too dark brown hair and greenblue highlights.
I went back 2 times but they didn''t manage to fix it.
First time, they washed it with that special shampoo and then put an auburn color over it (the shade I wanted and the colorist should have used in the FIRST place) It looked exactly how I wanted it, but it washed out again the next day from the blue highlights and the ends turned out much lighter.
That was when I decided that the whole colourshines obviously don't work for me, so I rather wanted to go back to the way I looked before.
I went back and they claimed they could totally remove all color with that special shampoo, so we did that. It did lighten the shade, but the green highlights stayed.
It was just Sebastian Cellophanes Colourshines, a vegetable colour, that''s why I refused to let them put any real colour over it.
I''ve been shampooing like crazy with babyshampoo for the high PH level and the john frieda blonde shampoo (and spent forever under a heat cap with deep conditioners)
My ends are blonde again; the top, which had hardly any highlights in it to begin with is light brown, but I still have shiny blue highlights in the middle now.
Any idea what else I could do to wash the colour out faster? Or make it fade..the blue that is. Any secret remedies?
My trust in salons is quite shattered by now, so I'm trying to wash out as much as possible before I go to another one.
I'm deadly scared that putting real chemical colours over it might go wrong again and somehow lock the vegetable colour in more.
I took tomorrow off, so I have 3 days I won't have to be seen in public.
I made an appt with the hideously expenisve, but really experienced colorist my mom goes to for monday afternoon.
Is it possible to bleach bluegreen hair again back to a blonde shade anyway?
Because I realized being blonde again (most of my hair is now) should be the easiest to achieve in order to have an even color.
It's really just a couple of inches on a few highlights in the middle, but the bright blue makes all my hair look so horrible.
I'll be forever grateful for any advice.

All of the above is very good advice, so I'll just add that I too am sorry a professional messed up your hair. Don't let it color your experience for the future too bad though, just because there are some bad ones running around, doesn't mean there aren't very good ones.

The only thing I would do with blue is go to a shade of red. To counteract blue, you need red or orange, and they don't offer those in the products that help you go blonde. I don't know what else would fix it. I'm not familiar with this "Sebastian Cellophanes Colourshines, a vegetable colour"...does that mean it's henna? If the blue is caused by henna there may be nothing you can do about it. I wound up with a haircut in the same situation. If it's not henna, then you can fix it, and I would consider a shade of red.