(1) Any seller who sells gasoline or special fuel to a purchaser through a keylock or cardtrol on which a refund may be claimed in accordance with 15-70-430, MCA, shall provide the purchaser with a statement of fuel purchased. The statement may be prepared as frequently as deemed necessary, but one statement must be issued at least every 30 days. To support the accuracy of the statement, the seller shall list or attach a list supporting all information used in the statement.