After-tax assessment or a book review? Pre-announcement or refusal of a VAT refund?
Solving problems with the Tax And Customs Administration is not just a matter of defending itself. Often the consultation with the inspector and explanation of the own situation is the solution.
Dealing with the Tax And Customs Administration is a balance between complying with reasonable requests for information and enforcing a real assessment of one's own situation, even if it was bad and cannot be properly discussed.
My advice is to get in touch when an investigation is announced or an attack is imminent. I'd rather you ask for help at too early a stage than later – afterwards. After all, the best possible outcome for you is largely determined by performing the right actions at the right time and omitting adverse actions.