How do I permanently delete a product on Amazon catalogue so it will not conflict with new listing?

Hi, I previously listed a clothing product on Amazon using ‘generic’ category which had no variations. Since then I have now had the product approved under brand registry and want to list it fresh with variations but am having issues creating the new listing. It is telling me it is the same as the old ASIN and will not let me put on a new listing. I have deleted my old product listing from the inventory and nothing is showing on the catalogue but is it still there somewhere in the Amazon catalogue? If so can someone advise how you completely permanently delete old listings and start afresh? I can’t amend the old listing as it won’t allow me to add variations. Any advice appreciated! Have contacted customer service but no helpful reply.