If a claim is in any respect fraudulent, or if any false declaration is made or used in support thereof, or if any fraudulent means or devices are used by the Insured or anyone acting on his behalf to obtain any benefit under this Policy, or if a claim is made and rejected and no action or suit is commenced within three months after such rejection or, in the case of arbitration taking place as provided herein, within three months after the arbitrator or arbitrators or umpire have made their award, all benefit under this Policy shall be forfeited.