The principles of equivalence and effectiveness, read in the light of Article 4(3) TEU, must be interpreted as not precluding national legislation, such as that at issue in the main proceedings, which allows a request for a refund of an overpayment of VAT to be refused where that request was submitted by the taxable person after the expiry of the five-year limitation period, although it follows from a judgment of the Court, delivered after the expiry of that period, that the payment of the VAT which is the subject of that request for a refund was not payable.