Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 62C, § 36A

If the commissioner determines that any tax has been assessed at an excessive amount because of departmental clerical error or that any payment has been received in error, he may, in his discretion, correct such error at any time and adjust the assessment accordingly or refund the erroneous payment without application of the taxpayer. Interest on any resulting refund shall be paid in accordance with section forty.

If the commissioner determines that he has made any payment in error, he shall notify the person to whom payment was made, in writing, making demand for repayment. If within 30 days thereafter the amount demanded is repaid in full, no interest shall be due. If repayment of the full amount demanded is not made within 30 days, the outstanding sum shall, without further action by the commissioner, be considered to be a tax assessed under this chapter as of the date of the demand, and subject to all the provisions thereof.