In the event that the debt has been paid, a procedure for requesting undue payment can be initiated. This procedure consists of requesting the refund of the tax debts that have been unduly paid, among others, for the following reasons: when the amount paid has been greater than the amount that should have been paid; when amounts that have been paid that have expired, when there is a material, arithmetical or factual error. The amount to be refunded will be the sum of the amount unduly paid plus the late payment interest in force during the period.