(1) A creditor may not take an assignment of earnings of the debtor for payment or as security for payment of a debt arising out of a regulated consumer credit transaction. An assignment of earnings in violation of this section is unenforceable by the assignee of the earnings and revocable by the debtor. This section does not prohibit a debtor from authorizing deductions from his earnings in favor of his creditor if the authorization is revocable, the debtor is given a complete copy of the writing evidencing the authorization at the time he signs it, and the writing contains on its face a conspicuous notice of the debtor’s right to revoke the authorization.