Judgment of the Court (Second Chamber) of 12 May 2021.#CS and Finanzamt Österreich, Dienststelle Graz-Stadt v Finanzamt Österreich, Dienststelle Judenburg Liezen and technoRent International GmbH.#Request for a preliminary ruling from the Verwaltungsgerichtshof.#Reference for a preliminary ruling – Common system of value added tax (VAT) – Directive 2006/112/EC – Article 90 – Reduction of the taxable amount – Article 183 – Refund of excess VAT – Default interest – No national rule – Principle of fiscal neutrality – Direct effect of provisions of EU law – Principle that national law must be interpreted in conformity with EU law.#Case C-844/19.