With your registration number , mail ID and using date of birth you can easily log in to download your MAT exam admit card. So don't worry just prepare well. And keep more than two copies of your admit card always.

Hello Shivank 

You need not to worry at this time. Just try to get the number from its website and call the administration department. You will definitely able to retrieve your admit card. And it myst be linked with your mail ID too. So keep checking your mail id. 

Moreover if possible you must try filling the form again. 

Good luck for your career ahead.