Upholding of the objection based on an arbitration agreement by means of an objection to lack of jurisdiction. Even though an objection to lack of jurisdiction is not the correct procedural vehicle for raising the existence of an arbitration clause, which must be raised as a preliminary matter in the answer, the decision shall not be annulled because the adversarial principle was observed and no prejudice was caused to the parties. Application of the principle of procedural flexibility or substantial compliance doctrine: