Challenge to the enforcement of an arbitration award. Controversy over a debt arising from a lease agreement. Allegation of nullity of service of process in the arbitration proceedings. The notice for the prior conciliation hearing was effectively frustrated; however, the respondent was subsequently notified by registered mail to comment on the debt calculations presented by the claimants. Defendant who failed to present a defense regarding this debt, which was the merits of the case, by its own choice. Absence of irregularity in the arbitration proceedings: