Pranav,
Have you looked in the log to see if Excel Importer reports any errors there? Sometimes I will see errors in the log with no error reported via the user interface. In Studio Pro, look in the console after trying to import this file for any errors. Screen shot below:
If there are no errors generated, the next thing I try is to import the spreadsheet into an entity with all columns having a string datatype. This eliminates any attribute type conversion issues that may pop up.
Hope that helps you move forward,
Mike