I went to my usual hairdresser 3 weeks ago and decided to go grey, I recently had my hair cropped and thought it would look great! After bleaching with low vol and olaplex for 85 mins and 3 toners...I was a lovely dove grey and loved it...until I washed my hair and the grey washed out on the ends (about 3 cm at longest bits). I tried all sorts of grey toners but nothing would grab and stay.
Visit 2 to hairdressers, had remaining grey removed and tried to go for a darker steel grey (she even put some black and clear colour in) walked out loving it...wash hair and the same thing happened (looked worse though because of the darker grey).
Visit 3, the ends looked dry so went very short π more lifting with low vol and olaplex, lots of joico treatment, followed by a permanent ashy grey blonde (had enough grey by that point and just really needed something to stick). Didn't wash my hair for 3 days....oh no!! I now have ashy sides and a blonde top, not a good look for me, been using black mascara mixed with joico oil to try and blend.....help me!!!!!! I think it's down to the fact that I had brown dye still on the ends from a few months before???
Have you tired Pravana silver?
I just done mine Manic panic lilac and cotton candy pink and now have grey silver hair (by mistake) and love it , I found the hair dresser that done my grey washed out very very fast as I had the darker grey on the roots and light on the ends, the roots stayed but ends didn't yet the MP turned it grey!
Your hair is too porous to hold the colour. For the timebeing, it would be best to use only direct dyes or purple shampoo, nothing that requires peroxide for the processing as this will make the problem worse. You could just wash it a few times with clarifying shampoo to get rid of the ash and it should be mostly blonde again.
After some protein treatments (K-pak reconstructor or Aphogee 2 step) and Olaplex standalone treatments, you could try again with a darker colour. There is more pigment so it's easier to get them to take on a porous base.