Dear aspirant,

After the fourth or the last round of counselling, the NLUs with vacant seats will release a notification stating the number of vacant seats in their respective courses. The notification will also state the procedure to be followed, which is basically filling up an online form, or an offline form , You'll get every information related to vacancies, starting from the number of vacant seats available to the list of candidates selected and the procedure to be followed post selection on the university's website,also as far as i know university itself lists vacant seats after final round of seat allotment and procedure for this is carried out by university itself, though still not to keep any 2nd thoughts i would also recommend you to contact WBJNUS authorities for the same too, though till 2018 procedure worked as stated above.

Hope this helps