Mass. Gen. Laws ch. 175 § 187C
A company issuing any policy of insurance which is subject to cancellation by the company shall effect cancellation by serving the notice thereof provided by the policy and by paying or tendering, except as provided in this and the following section, the full return premium due thereunder in accordance with its terms without any deductions. Such notice and return premium, if any, shall be delivered in hand to the named insured, or be left at his last address as shown by the company's records or, if its records contain no such address, at his last business, residence or other address known to the company, or be forwarded to said address by first class mail, postage prepaid, and a notice left or forwarded, as aforesaid, shall be deemed a sufficient notice. No written notice of cancellation shall be deemed effective when mailed by the company unless the company obtains a certificate of mailing receipt from the United States Postal Service showing the name and address of the insured stated in the policy. A check of the company or its duly authorized agent shall be deemed a sufficient tender. The affidavit of any officer, agent or employee of the company, duly authorized for that purpose, that such notice has been served and such return premium, if any, has been paid or tendered, as provided in this section, shall be prima facie evidence that cancellation has been duly effected.
If a policy is made payable to a mortgagee or any person other than the insured, notice shall be given as above provided to the payee as well as to the insured.
Policies subject to cancellation by the insured upon giving notice to the company may be cancelled by serving such notice in the manner herein provided upon the company or upon its agent who issued the policy.
Whoever knowingly and wilfully makes a false affidavit under this section shall be punished by a fine of not less than one hundred nor more than one thousand dollars or by imprisonment for not more than one year.
This section shall not apply to nor be deemed to prevent the termination of any policy by mutual consent of the parties, nor shall it require the payment or tender of a return premium upon the cancellation of a policy which provides for the payment of a return premium when ascertained or upon demand after cancellation.
Mass. Gen. Laws ch. 175, § 187C