(1) The amount, if any, included in a retail installment contract for insurance, which may be purchased by the holder of the retail installment contract, shall not exceed the applicable premiums chargeable in accordance with the rates filed with the state insurance commission. If dual interest insurance on the motor vehicle is purchased by the holder it shall, within thirty days after execution of the retail installment contract, send or cause to be sent to the buyer a policy or policies or certificates of insurance, written by an insurance company authorized to do business in this state, clearly setting forth the amount of the premium, the kind or kinds of insurance, the coverages and all the terms, exceptions, limitations, restrictions and conditions of the contract or contracts of insurance. The buyer shall have the privilege of purchasing such insurance from an agent or broker of his own selection; in such case, however, the inclusion of the insurance premium in the retail installment contract shall be optional with the seller. No holder shall unreasonably or arbitrarily refuse to accept coverage by an insurance company tendered by the buyer.
(2) If any insurance is cancelled, or the premium adjusted, any refund of the insurance premium received by the holder shall be credited to the final maturing installments of the contract except to the extent applied toward payment for similar insurance protecting the interests of the buyer and the holder or either of them.