In Kemper v. Schardt (1983) 143 Cal. App. 3d 557, the parties entered into a written contract for the respondent to provide architectural services to the appellant. The contract contained an arbitration clause specifying arbitration of all disputes between the parties. The respondent sought arbitration following a dispute regarding payment for services under the contract. The appellant fully participated in the arbitration after which the arbitrator issued an award in favor of the respondent. Thereafter, the appellant petitioned the trial court to vacate the arbitration award on the ground that the arbitrator acted in excess of his authority. In particular, the appellant argued that he was German and could speak English, but could not read it, and the respondent had fraudulently included the arbitration clause in the contract and the arbitrator exceeded his powers. The Court of Appeal concluded: "In subjecting his person to arbitration and in participating in the arbitration process both through the presentation of witnesses testifying on his behalf and through his own direct testimony, appellant in effect submitted to the arbitrator's authority to decide both the substantive issue regarding liability for payments and the issue of whether there was a valid arbitration agreement. Consequently, he cannot now be heard to complain that the arbitrator was without jurisdiction to determine the issues because fraud vitiated the arbitration clause in the agreement." (Id. at p. 560.) "An arbitrator may herein decide any issue which the parties willingly present to it. It is too late for appellant to now complain that the arbitrator was without jurisdiction to determine the issue. " (Id. at p. 561.)