A general acceptance clause of contractual provisions ("all provisions contained in the preceding articles have been defined and accepted by the parties in adversarial proceedings") is equivalent to the specific written approval of the arbitration clause required by Article 1341, paragraph 2 of the Civil Code, especially when there exists a symmetrical relationship between the parties and the signature has occurred on multiple contracts containing both the arbitration clause and the general acceptance clause.
The existence of a valid arbitration clause results in the nullity of the payment order issued by the ordinary court and the declaration of that court's lack of jurisdiction in favour of the arbitrators.