It shall be the duty of every commission merchant upon receipt of any farm products for sale on commission to make and keep a correct record thereof, showing in detail the following with reference to the handling, sale or storage of any such farm products: the name and address of the consignor, the date received, the grade, quantity and condition when received, the amounts sold, the date of each sale, the price for which sold, itemized statement of the expenses connected with or incurred in making sale and to whom sold, including the complete name and address. A copy of such record and account of sale of such farm products, together with remittance in full of the amount realized by such sale, less expenses and commission, shall be mailed to the consignor within 48 hours after the consummation of and in no case shall such remittance be delayed for a longer period than seven days after the date of consummation of the sale of such farm products or any part thereof, unless such longer period shall have previously been agreed upon by contract in writing between the consignor and such commission merchant. It shall also be the duty of every commission merchant to retain a copy of every record of account of sales made as required by this section for a period of one year from the date thereof, which copy shall at all times be available for and open to the inspection of the commissioner. The burden of establishing the accuracy and correctness of any such record or account of sales or copy thereof shall rest upon the commission merchant making such record or account of sales.