anonymous Fox hack is a vulnerability in WordPress 5.5 if you are on WordPress 5.5 kindly update to a newer version of WordPress.
FIX
You are not able to log in to your WordPress account to edit your website, because someone changed your password and username.
REQUIRE
you need cpanel login to FIX this issue and recover your website.
STEP 1:
login to your cpanel with your Id and password of cpanel

STEP 2:
go to you phpMyAdmin database

STEP 3:
find user database (it has name like wp_user * something)

STEP 4:
in that data base click on table, then there will be list of all users, find your hacked one user(user with username of anonymous fox) and update it’s username and password.

STEP 5:
you can also create new user and use that credential to login into your wordpress admin.
enjoy.