Mass. Gen. Laws ch. 167B, § 9
(a) For each electronic fund transfer initiated by a consumer from an electronic branch or point-of-sale terminal, the financial institution holding such consumer's account shall, directly or indirectly at the time the transfer is initiated, make available to the consumer written documentation of such transfer. The documentation shall clearly set forth to the extent applicable:
(6) a transfer identification number which provides a permanent audit trail.
The information required to be disclosed under clauses (4) and (5) of this subsection shall be provided in readily understandable language; or capable of being explained in readily understandable language.
(b) Where a consumer's account is scheduled to be credited by a preauthorized electronic fund transfer from the same payor at least once every sixty days, except where the payor provides positive notice of the transfer to the consumer, the financial institution shall provide notice by one of the following means:
(3) the institution shall provide a readily available telephone line that the consumer may call to ascertain whether or not a transfer occurred and shall disclose the telephone number on the initial disclosures required by section eight and on each periodic statement.
The means of notice elected by the financial institution shall be disclosed to the consumer in accordance with said section eight.
(c) A financial institution shall provide each consumer with a periodic statement for each account of such consumer that may be accessed by means of an electronic fund transfer; provided, however, that if two or more consumers hold a joint account from or to which electronic fund transfers can be made, the financial institution need provide only one set of disclosures for each account. Except as provided in subsection (d) or (e), such statement shall be provided at least monthly for each monthly or shorter cycle in which an electronic fund transfer affecting the account as occurred, or every three months, whichever is more frequent. The statement, which may include information regarding transactions other than electronic fund transfers, shall clearly set forth in meaningful sequence:
(g) If a financial institution discloses to a person other than the consumer or any other person who is a party to the transaction information regarding an electronic fund transfer beyond that necessary to effect the transfer or to prepare a periodic statement, within ten business days the financial institution shall mail or deliver to the consumer a written notice including the following information: