Any person not a resident of this state who engages in business in this state, as defined in § 44-18-23, shall, as a condition precedent to engaging in business in this state, and by engaging in business in this state, consent that any process issued in the enforcement of the provisions of chapters 18 and 19 of this title may be served upon the director of the department of business regulation as agent of that person. The process may be served by leaving a copy of the process in the hands of the director of the department of business regulation or in the director’s office with someone in charge of the office. The service is sufficient service upon the person; provided, that notice of the service and a copy of the process, at least fifteen (15) days before the return day of the process, is sent by registered or certified mail, postage prepaid, by the tax administrator or the administrator’s attorney of record, to the person’s last known address, and the sender’s registered or certified mail receipt of sending and the tax administrator’s or the administrator’s attorney’s affidavit of compliance are appended to the process and entered with the declaration. Service of process in the manner provided for in this section, under the circumstances specified in this section, is of the same force and validity as if served upon the taxpayer personally within this state. Nothing in this section limits or affects the right to serve process upon a person not a resident of this state within this state in any other manner now or hereafter permitted by law.