Article 21 of Law of Evidence

An endorsement by the creditor on the debt instrument, in his handwriting and without his signature, indicating discharge of the debtor shall constitute evidence against him until the contrary is proved. Such an endorsement by the creditor shall also constitute evidence against him even if it is neither in his handwriting nor signed by him, provided that the instrument has never left his possession. The same rule shall apply if the creditor records in his handwriting, without his signature, an indication of the debtor's discharge on another original counterpart of the instrument or on a receipt, and the counterpart or receipt is in the debtor's possession. Chapter Three Application to Compel a Litigant to Produce Papers in His Possession