Is it safe to put dye on top of prelightened hair? To get rid of the yellow and acheive ash blonde?

I prelightened my hair, which was originally dark blonde, but had been dyed a lighter. My plan was to strip my hair back to its natural dark blonde, which the prelightner said it would do on the packet if you followed 'method 2', instead of 'method 1' which would lighten hair by a good few shades. Well, something obviously had gone wrong in the process and my hair came out a disgusting pale yellow colour. Giving up any hope of getting my natural hair colour, i decided upon having my hair a light ash blonde, which would suit me. Funnily enough, I had a spare pack of ash blonde hair dye which I had brought only a few weeks ago but not gone ahead with it. I have read and heard that dying blonde prelightened hair that has turned yellow with ash blonde dye will neutralise the yellow. Thing is, on the back of the pack, it says 'do not use on previously bleached, PRELIGHTENED, or highlighted hair'. But prelighening hair and then dying it is how platinum blond hair is done, so it must be safe?

Is it safe to put dye on top of prelightened hair? To get rid of the yellow and acheive ash blonde? PLEAS HELP

be very careful as over-processing your hair can make it brittle and split the ends.