Another bad hair colour experience

[Balayarse]

Until a few months ago I had regular blonde foil highlights. I liked it, but the toner always washed out in three washes, leaving just white blonde. The sides were always lighter than the back too, as apparently my hair lifts differently on the sides. The hairdresser tried a darker toner, but then I would walk out as a brunette then 2 weeks later be white blonde again!

After a few months I tried a new hairdresser. I went there with very grown out blonde highlights.
We agreed on a beige balayage (pic 1 for inspo) with a root smudge.
I walked away with yellowy blonde hair which I hated, but I was hoping it might calm down.
Three washes later this is what it looks like. The back is ok as there is some dimension, but the sides are just light yellow. And the top is yellow with a horrendous root line.

The 'root smudge' has been badly done I think. It's certainly worse than the last hairdresser used to do. But do I just have shit hair that doesn't take properly? What do I have to ask for to get something with a bit of dimension, and a nice colour?! I'm so fed up.

Please excuse my fluffy unstyled hair. It's a work from home day...

You need some purple shampoo on it to get rid of the brassy tones, are you regularly using purple shampoo between appointments?

Agree the root smudge is a bit poor, but if that's the reference photo shown to hairdresser though there's no roots visible in the reference so there's maybe been a misunderstanding of what you're after?

As for the hair colour, that colour blonde requires lots of maintenance, usually a combination of purple shampoo (as suggested above) and toners you can use at home. When I had similar I had a purple shampoo I used every other wash (with a deep conditioner because that stuff dries your hair out) and a toner I'd do every 4/6 weeks. Both from a brand my hairdresser recommended. I'll see if I can find the link.

I also did a bleach shampoo (at home bleach kit diluted with shampoo and left of for a shirt tine) in the past when I wanted a bit more lift to the blonde, obvs bleaching at home isnt for everyone though and its more of an all over thing without the depth you get from balayage.

These ones! uk.wella.professionalstore.com/category/wella-professionals/colour/color-fresh

Haven't used for a while as I'm embracing the greys 😅 but the Ash blonde removed the yellow when my hair was bleached and it settled out to the type of colour in your inspo pic.