Someone With Experience In Dyeing The Hair System? I Am Doing Something Wrong

[F.Coronilla]

Hello

Well finally i found the dye colour that match my own colour, its a 8.43, i am using montibello cromatone,
the problem is that after a few days the colour change dramatically, like turn light blond green, its really really diferent and happened like just after 4 days, its a permanet dye that is very used in my country and it last a lot,

what can i be doing wrong?

thanks a lot

 

[vinn]

It's most likely not your fault, dyes from a box rarely ever look natural.