Hair will lift but not deposit color?

So, I have natural level 7 hair that lifts very easily, but color doesn’t seem to deposit? I’ve been testing on just my roots where I have growth with 20 volume developer and tried both a 8 and 10 level blonde dye and it doesn’t change the color at all. I usually process for 30-45 minutes. I was hesitant to use a higher volume developer because it already lifts so easily. Or would leaving it on longer help the dye penetrate more? Or am I not lifting enough so the color doesn’t show up?