Purple hair won't fade

If you could post a picture we could advise you
On whether a dark brown would cover what you have now. Judging from the fact that you want a dark colour I'm guessing a brown dye would cover it fine. Also have you tried colour removers etc? What fading treatments have you done?

It is kind of bright purple but a bit matted it really is purple one can't miss it, I don't want to end up with dark brown or black hair with a purple hint to it :/

I have tried anti dandruff, vitamin c, hot oil, anti dandruff with vitamin c and anti dandruff with baking soda, washing my hair with hot water.. Haven't tried any colour remover cuz last time I used on my hair got really damaged and only faded it like a shade lighter than it was before so I haven't much trust for it after that..

Color removers dont damage hair, they do make it very dry but that can be fixed with a good deep conditioning after.
I would recommend trying the color b4 fashion colors. It has a very good pre-claryfing treatment which strips color out very well.

Yup, colour removers are non damaging. I would suggest trying it out. Also the bleach powder with shampoo and oils technique has worked well for quite a few people on the forum to get rid of stubborn hair colours. (there's a thread on it in the tutorials section)