Collar dye bleeding, and staining fur

Hello! The title is pretty self explanatory. But in short, my dog’s collar (Black) keeps bleeding onto her fur (White) making it a grayish/blackish color. I have tried vinegar and salt to set the dye, I’ve also tried a warm water soak to try and remove excess dye. Yet nothing seems to make the problem any better, does anyone know how I could solve this? Or do I just bite the bullet and find a different color collar?