Last date to apply is over but event date is not

I could not confirm my presence after getting an interview call from “Attre”. Last date to confirm was yesterday i.e. 12feb 2:00 pm. I was eagerly waiting for an interview call from many months, I want to attend this interview at any cost. Please help me. Event date is on 15feb 2017.
My Elitmus login ID is

Looking forward for your valuable repies