Hey Ankit!

You haven't mentioned the name of the college or university and course for which you want to pay the admission fee. Make sure that you read the instructions for payment of the admission fee provided by the college. It could be that the portal opening time for payment of fees would have been scheduled if mentioned in the instructions. If you are sure that you are thorough with the instructions and there is no fault from your side, then please contact the help desk. The number or email must be provided on the website of college.