Judgment of the Court (Ninth Chamber) of 22 January 2026.#RM and EM v Santander Bank Polska S.A.#Request for a preliminary ruling from the Sąd Okręgowy w Warszawie.#Reference for a preliminary ruling – Consumer protection – Directive 93/13/EEC – Unfair terms in consumer contracts – Article 6(1) and Article 7(1) – Mortgage loan agreement indexed to a foreign currency and containing unfair terms – Effects of the finding that a contractual term is unfair – Void agreement – National case-law providing for two independent claims for restitution – Consumer action seeking repayment of monthly payments made under the agreement – Claim of the seller or supplier corresponding to the amount of the loan – Recovery – Right of the seller or supplier to raise a plea of set-off of its claim against that of the consumer – Rules on the award of costs – Dissuasive effect of the prohibition on unfair terms – Principle of effectiveness – Obligation to interpret national law in conformity with EU law.#Case C-902/24.