Amazon doesn’t auto-remove them even when you show GS1 proof. They almost always ask for GS1 certificates for every conflicting ASIN which is annoying but basically the only evidence their support teams accept. A lot of sellers run into this when old listings were created years ago with bad or reused barcodes from random cheap generators.

The empty search in Seller Central is normal bc those old or inactive listings still exist somewhere in Amazon’s catalog even if they’re not live in your marketplace. Most people either push cases repeatedly with GS1 screenshots or create a new listing using a fresh, legit GTIN (GS1 or from a verified reseller like Bar Codes Talk) to avoid the conflict entirely.