On 22 November 2018, the ECJ issued a judgment that revived a long-standing dispute regarding the VAT treatment of non-refundable payments. In this article, the author provides an overview of the evolution of the ECJ's understanding of the nature of cancellation charges and seeks to clarify the criteria for differentiating between charges subject or not subject to VAT. The author analyses the impact of the latest developments in this discussion on the evolution of the substance-over-form doctrine in the field of VAT.