Me. Rev. Stat. tit. 9-A, § 9-306

A consumer is not obligated to make payments on a consumer credit transaction to any creditor, other than the original creditor, until the consumer receives notification of assignment of rights to payment and that payment is to be made to the assignee. A notification that does not clearly and conspicuously identify the rights assigned is ineffective. If requested by the consumer, the assignee must seasonably furnish reasonable proof that the assignment has been made and unless the assignee does so the consumer may pay the original creditor.