Michigan Compiled Laws, Chapter 445. Trade and Commerce § 445.2504

Sec. 4. (1) A person who sends or causes to be sent an unsolicited commercial e-mail through an e-mail service provider located in this state or to an e-mail address held by a resident of this state shall not do any of the following:

(2) If the recipient of an unsolicited commercial e-mail notifies the sender that the recipient does not want to receive future unsolicited commercial e-mail from the sender, the sender shall not send that recipient unsolicited commercial e-mail either directly or indirectly through a third party.

(3) A sender of unsolicited commercial e-mail shall establish and maintain the necessary policies and records to ensure that the recipient who has notified the sender under subsection (2) does not receive any e-mail from the date of the notice. The sender shall update its records under this subsection not less than every 14 business days.