How do Remove troublesome phishing adware?

2 Days ago on a site I often used every page i clicked on started redirecting me to this advertisement for Mackeeper, a program I know is a big scam. This would redirect from every page and if you tried to close the tab while it was still on there, there would be an error and you'd be forced to quit Safari. I deleted my cookies for the site many times, I went through my Libraries, preferences, launch agents, and app accessories deleting anything that looked remotely related and nothing seemed to work. I concluded that it must be a problem with the site itself, but recently it started on other sites as well. Most recently after reading threads on this side i got the program Malwarebytes which scanned my computer for these problems, after deleting every single issue to the point where it comes up with nothing when i scan now, this problem still persists. What do I do?