Strange hair…

I think you should try mixing your own dye. Buy a colour and a 20 vol creme developer and mix it yourself because you can control the consistency of the mix. Also, it recommends leaving it in between 20 mins and 45 mins. Leave it in for the maximum recommend time plus 5-10 minutes extra.
The professional dyes you mix yourself from hairhouse warehouse/price attack are a lot stronger than the premixed packaged ones from the supermarket.
Also, you can purchase a spray that you put on your hair before applying dye, and it opens the follicals.

Hi CJIreland! Have you only tried DYI dyes, or have you also tried the hairdresser? I think you may need professional help here. If you keep dyeing your hair like you have yourself, you may be causing more damage. xo

What brands have you tried????

make sure you hair is not oily, because oily hair makes it very hard for dye to stay on, also i suggest talking to a hairdresser, if you dont want to spend money thats fine, just get advice, remember advice is always free

Oh…if you are already using a salon shampoo/conditioner then I would be looking at the kind of water you are washing your hair in (bore water contains a lot of minerals which will make hair impossible to colour).

If you are using a shampoo/conditioner from the supermarket/pharmacy, it is probably a build up of silicone on your hair preventing the colour from penetrating the cuticle. These shampoos/condtioners contain a man-made silicone which builds up every time you use it (it adds another layer each time you shampoo). Salon shampoo`s/conditioners contain natural plant derived silicone which doesnt build up. Each time you wash with a salon shampoo, the old silicone rinses out and a fresh layer put in its place. Silicone is what makes your hair feel nice but long term build up makes hair dull, gritty to feel and resistant to colour. To remove a buildup of silicone you need a clarifying shampoo…use it daily for about a week, then once a week thereafter (alternated with your fave salon brand shampoo)

May be a poor brand for your hair type. Have you tried different brands?