(a) No gas corporation shall discontinue the supply of gas for nonpayment of bills rendered for service, or for failure to post a required deposit, until:
(1) at least five days after written notice has been served personally upon the person supplied;
(2) at least eight days after mailing written notice in postpaid wrapper to the person supplied, addressed to such person at premises where service is rendered; or
(3) at least five days after the person supplied has either signed for or refused a registered letter containing written notice, addressed to such person at premises where service is rendered.
(b) If the person supplied has specified to the company in writing an alternate address for billing purposes, the notice authorized under paragraphs (2) and (3) of subdivision (a) of this section shall be sent to such alternate address rather than to the premises where service is rendered.