Before any such cancellation or forfeiture can be made for the non-payment of any such premium the insurance company shall notify the policyowner of any such policy that the premium thereon, stating the amount thereof, is due and unpaid, and of its intention to forfeit or cancel the same, and such policyowner shall have the right, at any time within thirty (30) days after such notice has been duly deposited in the post office, postage prepaid, and addressed to such policyowner to the address last known by such company, to pay such premium: Provided, That in lieu of the notice hereinbefore provided, in the case of policies providing for a period of grace of not less than thirty (30) days, or one month, for the payment of premiums and containing any provision for cancellation or forfeiture in case of nonpayment of premiums at the end of such period, the insurance company may, not more than thirty (30) days prior to the date specified in such policy when any premium will become due and payable without grace, in like manner notify the policyowner under any such policy, of the date when such premium will fall due, stating the amount thereof, and its intention to forfeit or cancel the same if such premium be not paid within the period of grace provided in the policy; and any attempt on the part of such insurance company, within six (6) months after default in the payment of any premium, to cancel or forfeit any such policy without the notice herein provided shall be null and void. The affidavit of any responsible officer, clerk or agent of the corporation authorized to mail such notice, that the notice required by this section has been duly addressed and mailed by the corporation issuing such policy shall be prima facie evidence that such notice has been duly given.