This letter looks like a standard request for clarification in the case of so-called cross-controls. Probably the tax office responsible for cfound analysis is examining the company's books/declarations and wants to confirm the reality of the transactions presented by cfound. I assume that more people/entities have received such letters.

In this case, it is necessary to search in the history whether there were such transactions, in what timeframe, and respond according to the real course of the purchase.

The 7-day deadline is quite arbitrary, and after contacting the tax office, the time for a response can be extended. Additionally, contact with the tax office will allow for clarification on what the inquirer is actually interested in.

ccFound - Urząd Skarbowy