Opinion of Advocate General Campos Sánchez-Bordona delivered on 30 November 2023.

UA v 'Eurobank Bulgaria' AD.#Request for a preliminary ruling from the Apelativen sad - Sofia.#Reference for a preliminary ruling – Free movement of capital – Payment services in the internal market – Directive 2007/64/EC – Concept of ‘payment instrument’ – Power of attorney of an agent acting on behalf of the account holder – Copy of the power of attorney with an ‘apostille’ certificate – Articles 54 and 59 – Consent to the execution of a payment transaction – Concept of ‘authentication’ – Unauthorised payment transactions – Liability of the payment service provider for those transactions – Burden of proof.#Case C-409/22.