Unfortunately it appears that these duplicates are all intentional. They are set up like eBay pages with information on VGA grade, sealed or boxed, cart quality, etc.
Edit:User is banned, looks like a lot of the items were posted in NES[US], Sega Genesis[NA], and Atari 2600 accessories and hardware. I'll be going through them when I have time this week, but posting any you find here would be greatly appreciated.