Article 39 sets the timeline for taxpayers to claim refunds for wrongly collected taxes and penalties. The right to request a refund expires five years from the date the taxpayer becomes aware that the collection was unjustified. This period can be interrupted if the taxpayer sends a formal request to the Authority via registered letter. By defining this five-year window, the Law provides taxpayers with a clear timeframe to correct payment errors while ensuring that the state's financial accounts are not subject to indefinite refund liabilities for past fiscal periods.