UCAS reference question

Have you sent your application off on your end? He won't be able to finalise your reference until you pay and send your application.

Hello

I have a question about my reference.
My tutor says he has sent off the reference but when I logged onto apply it said the reference is still on going. I've tried contacting him this evening but I can't reach him. I was going to wait till tomorrow to ask because the reference is the last part of my application that's not done yet so it's literally just that and I can send it off.

The problem is, he mentioned something about it saying he has to send the reference off three working days before the deadline and I'm worried that by tomorrow it'll be too late. Is the three working days thing true? Or did I just misunderstand something.
I'm an international student by the way.

Thanks