With product creation on Amazon you can find the same products listed more than once or different versions of the same product split over multiple listings. In these cases Amazon do merge listings if you report them to Amazon Seller Support.
To do this login to your Amazon Seller Central account and lodge a case with their support team. Make sure to include the following details in the email,
- A quick description of what the issue is
- The ASINs (and links to) the duplicates
- How you know why they are duplicates
- A link to the Manufacturers website displaying the product and Barcode or
- An image / images displaying the products packaging with Barcodes and details visible
If Amazon need any further information they'll reply back and let you know.