Hello, 

As per your question, i would say that as your college staff didnt generate registration unique code. As also your admit card is out, so you must not be able to get your admit card out. 

Now you first try to log in and then generate your unique code then only you will be able to proceed further steps. Then only you csn register your admit card or try to reset it and then fill it up freshly. 

Check out the way in its official site to download the admit card.

Good luck