Cant log in-Unjust late fees

Tried to pay bill when it was due on 12/2, website was slow. Eventually said it accepted my payment.  This morning, was saying I never paid and is late.  (Noticed today that it never drafted my bank acct, so I checked it).  Now, on my lunch break...trying to pay again.  When I hit enter to log in, it refreshes the page and takes me back to the log in screen.  So...still cant pay the bill, and strapped with late fees that I should not have!