login to www.routerlogin.net fails when using factory password and admin?

To make a long story short, my roomate just moved out and he had control over the routers admin login. He also had an additional router plugged in to my router for some odd reason. He also disabled the 2.4 Ghz signal and kept the 5 Ghz online.

Since he moved out i tried logging in to get the 2.4 Ghz back online but I am unable to with the factory username and password. It gives me this error message:

You are currently logged in from another device. There can be only one device logged in at a time. If you log in from this device, the other device will be logged out. Do you want to proceed?

I click proceed and entering the username and password and the window to enter credentials just pops up again, i click no and nothing happens. 

What do i do?