When a policy issued on the installment plan is canceled, in accordance with section 3929.19 of the Revised Code, the company issuing such policy may collect of the insured the customary short rates for the time the policy has been in force, said rates to be computed on the full term of insurance mentioned in the policy as charged by such company. On receipt of such short rates, it must return all installment notes then unpaid and refund to the insured any premium collected in excess of the short rates.
R.C. §3929.22