Hi there. 

This isn't the right way to contact a student of any University, whatsoever. 

I'd suggest you to search the page for Presidency University, Kolkata on social media platforms like Facebook and Instagram to make contacts with students studying there. You'll find many groups and pages on Facebook. A simple search would be enough to get you connected. And if not that, if you are a Kolkata resident, just go to College Street and talk to people at Presidency. They will surely help you out. 

Feel free to post further questions. 

All the best.