Ungating—New Seller

Been having some issues with ungating as a new seller, as Amazon requires additional documents to check my supply chain and authenticity of the products, I believe. i tried to ungate Head and Shoulders, and received how I need to provide invoices from supplier’s supplier, letters, etc to validate the supply chain. My supplier says this is not possible. I tried to search for another supplier, ordered, received the item, but now the brand is completely gated. Cannot even reapply for the brand. When I type in ASIN under “Add products”, the item pops up with the button “Not available”. I have inventory at home. Cant return it. What is next?