Letter of Authorization amazon.de

Hello team, I need your help.

Recently, I started creating an account on Seller Central Amazon for amazon.de, and I encountered an issue. Amazon is requesting a letter of authorization, and I found guidelines on how the letter should look. I wrote the letter and sent it, but without success. I tried again with some changes, but the result was the same. I even contacted Amazon, but I haven’t received a response.

I created the letter in various variations:

Where my company authorizes me for selling. Where I authorize myself for selling, etc. In total, I made 7 attempts with seven different combinations. However, with each letter, Amazon returned the same errors: the letter is unclear, not signed by the appropriate person, the listed individuals do not match, the letter has expired, and so on. I receive the same errors in every response, regardless of the changes I make.

What is happening, and how can I start selling on Amazon?