To either make changes to or delete the duplicate items, you can
download a CSV of your listings,
use Excel to find duplicate listing data,
then re-upload the CSV to 3Dsellers.
Steps to remove or edit duplicate eBay listings:
1) Navigate to Products → Listings Manager.
2) Select all of your listings.
3) Choose Export to CSV from the Bulk Actions menu.
4) Use Excel's Find Duplicates feature to separate the duplicates from the other listings. You can search the Title, SKU, or Item Specific fields to find duplicate listings.
Don't let Excel auto-format the Item IDs. Click here to learn how to prevent this.
5.2) To change listing data in the duplicate items (e.g. update the titles)