Please help my gf - yellow/orange after ash blonde dye

Okay so... This will be a bit detailed but I am now desperate for help. I've been doing my gfs hair for a couple years now with no issues. Let's just say when we tried to bleach her whole head last year is when problems arose. Her hair was darker (brown/light brown) so It needed to process at least twice before getting the color we wanted AND at the time neglected to get a toner for directly afterwards - oops. But she freaked after the first go round and refused to let me bleach again. Anyway,  this left her with quite brassy hair and she was in a panic so we went and got some ashy brown and dyed over it. It's been fine since other than having to dye it once a month bc the brassy tones always return again. So this is where I am now..

She decided she was wanted to try going a little lighter (ash blonde). So her hair was a medium/light brown with a bit of golden looking browns towards the ends and had caramel highlights that had been in for a couple of months as well. So we get Mystic Divine permanent color in natural ash lightest blonde and a 30v developer. I applied this ab half an inch down from the root to try to avoid any super brightness from happening in case it decided to really lighten up.  We left this on for about 50 mins and she washed. Well... It did really lighten up the hair. In fact it acted as a mild bleach. The ends of her hair were pretty bright  orange with the tops being more of a yellow. We did have a wella t-28 toner on hand so we used that in hopes it'd make things better. Which.. It did. But not enough. The orange tones are much more muted now and the blonde is a pale yellow color. I can try to get pics when she gets home.

My question is.. What do I do? She is really upset with how she looks right now and just wants it to be pretty as we've been battling it ever since the bleach last year. Should we try to tone it again? Should we try a slightly darker ash color? I want to avoid bleach as she's terrible of it and her hair I'm sure is already stressed (this process all happen last night)  *ott*

And yes I'm know all of this could have been avoided with a salon lol. We are just the.. Do it yourself, have fun and maybe save money type of people lol. Clearly that wasn't the best option this go round. Please help me help her!