There are many tools available online to delete duplicate data from a CSV file. I was recently searching for a tool, but one of my close friend suggested the MacSonik CSV Duplicate Remover. This utility can remove duplicate data from CSV files easily. Using this tool, you can delete duplicate contacts from VCF/vCard files. It scans the chosen files, finds duplicates, and removes them quickly. Also, this utility provides a free demo version that allows you to remove duplicates and save 25 records without any cost.
To know more: https://www.macsonik.com/csv-duplicate-remover/