My Amazon stock has been lost. How do I recover it?

Hello, I have been selling for a year on different platforms but just started on Amazon with the same products I sell. There are a lot of sellers selling the same products so I decided to use buybox and listed a few products not knowing those sellers are trademarked. To my surprise, I won the buybox and sold 5 items within hours but this morning 2 of my listings were blocked by amazon because both sellers have reported them as infringed products and now amazon wants an explanation. Just to be on the safe side, I closed all my listings for now.

Amazon now wants – An invoice, letter of authorization, or a licensing agreement from the manufacturer or rights owner demonstrating that your products are lawful.

What are my options in this situation?
I source the products from China so do I need to provide amazon with invoices etc?
Do I need other seller’s permission for buybox?
Now all of my stock is stuck somewhere in Amazon Warehouse and I don’t know how to recover it. Is there a way that can allow me to transfer that stuck stock on another listing? or have I lost all of my stock permanently?

Any help will be much appreciated.