Wigs Mohair dyeing troubles

I've been trying to dye natural mohair with hair dye, and it hasn't been going well
The problem is only the base color is able to penetrate.
Now I understand that it is hard for dye to penetrate mohair, and taking this into consideration I left the dye on for a couple of hours. This didn't work and looked the same as if I had left it on for 45 minutes.
I also let the hair soak in vinegar water for a few hours before applying the color (I rinsed off the vinegar and water mixture and let it air dry completely before applying the dye), and this also did nothing even after letting the dye process for 3 hours.
I have been using both 'Schwarzkopf' and 'Zotos age beautiful' brands of dyes, and both have the same result. For the darker color, I've been using a 30 developer. Perhaps it's the brand of dye or level of developer?
Does anyone have tips or any ideas of what I'm doing wrong?
Thank you so much in advance!