Opinion of Advocate General Kokott delivered on 4 June 2020.#E. Sp. z o.o. Sp. k. v Minister Finansów.#Request for a preliminary ruling from the Naczelny Sąd Administracyjny.#Reference for a preliminary ruling – Common system of value added tax (VAT) – Directive 2006/112/EC – Article 90 – Reduction of the VAT taxable amount – Total or partial non-payment of the price – Conditions imposed by national legislation for the exercise of the right to reduction – Condition that the debtor must not be the subject of insolvency or winding-up proceedings – Condition that the creditor and the debtor must be subject to VAT.#Case C-335/19.