I keep being redirected to a myatt-wg website?

so I think my browsers have been hijacked

every time I try to go anywhere, like youtube, wiki, macsafe, even the legit at&t site, it redirects me to the bogus myatt site. the connection to the mail, imessage, and the app store apps are also obstructed. it's affection chrome and safari as well. I've tried deleting and blocking cookies, resetting my modem, anything I could do that wouldn't get me redirected. the apple site is maybe one of three sites that I can actually access. I can't access my mail and accept any downloads that might fix it, nothing. I'm stuck. I'm getting really anxious, and I also don't want to take it in unless I absolutely have to, but every link that'll provide scans and fixes keeps getting redirected.