Unable to list on generic items listing, help please

Hi, im having an issue listing on a generic item and the help is useless from amazon (as we all know). So ive tried listing a product ive purchased and everytime i click new, sell this product it says

“You cannot change a product detail page or add offers on another seller’s generic product, or copy the product detail page to another store. If you want to sell a generic product, you must create a new product. To create a new product, follow the process outlined in Add a Product tool. For more information, go to Amazon Generic Product Policy”

Im not trying to change the product details page, im trying to list using the same marketplace. Ive tried everything, tried listing the product as “this item isnt on amazon” got to the page where you select price etc but when i click on “does this item contain batteries” i get the same pop up again. I just want to list the item ive purchased on there asin, as its got alot of sale per month.

Any help appricated

Thanks