Mass. Gen. Laws ch. 258C § 14
When a person files a claim pursuant to this chapter, no health care provider, as defined in section 1 of chapter 111, that has been given notice of the claim shall conduct any debt collection activities relating to medical or dental treatment received by the person in connection with the claim until an award has been made on the claim or until the claim has been denied. The period during which the health care provider shall be prohibited from conducting debt collection activities pursuant to this section shall be excluded in determining the applicable limitations period for commencing an action to collect the debt. For the purposes of this section, "debt collection activities" shall mean repeatedly calling or writing the claimant or threatening to turn the matter over to a debt collector, as defined in section 24 of chapter 93, for collection, enforcement or filing of other process; provided, however, that "debt collections activities" shall not include the routine billing or inquiries about the status of a claim.
Mass. Gen. Laws ch. 258C, § 14