According to Article 19 of the Arbitration Rules [of the Chamber of Mediation and Arbitration of Paraná – CMA/PR], the initial notice must first be served at the address provided by the claimant, by means of correspondence with acknowledgment of receipt. Should this prove unsuccessful, it shall be incumbent upon the claimant to take steps to obtain the respondent's current address. If such attempts fail, the CMA may resort to notice through the Registry of Instruments and Documents, based on the information provided by the claimant, and, finally, to notice by formal public announcement, which shall be published once in a widely circulated local newspaper. Compliance with the rules. Validity of the initial notice of the arbitration proceedings and of their continuation without the defendant's answer. Award of court-ordered attorneys' fees against the plaintiff in the action for nullity of the arbitration award on grounds of malicious use of process: