Every member of a county mutual insurance company which sustains loss shall notify the company immediately after the loss is sustained. The company shall assign the loss to be adjusted in the manner provided in the insurance policy of the company. If the parties are unable to agree upon the amount of the damage, the claimant and the company each shall choose a disinterested party to constitute a board of arbitration to settle the loss. If the parties cannot agree, the parties shall choose a third party to act with the parties. The board of arbitration may examine witnesses and shall determine all matters in dispute, and the decision of the arbitration board is final.