a). Register on SCORES portal Home - scores.sebi.gov.in

Mandatory details for filing complaints on SCORES:
  i. Name, PAN, Address, Mobile Number, Email ID

b). Benefits:
   i. Effective communication
   ii. Speedy redressal of the grievances

You may also download the SEBI Scores app to log a complaint
Android: https://play.google.com > store > apps > sebiscores
iOS: https://apps.apple.com > app > sebiscores