Calls come through in a series of three. Typically within minutes of each other. Additionally, a call will generate from 978-722-0402. No message is left from any line. This is most likely a telemarketing or spam call. Worse, this is harassing and spam sent to a business phone on the no-call list.

I guess you didn't bother to read where business lines are not eligible to be on the DNC?  As a business person shouldn't you be taking the time to read before signing up for stuff?
What the Do Not Call lists covers and doesn’t cover and why:  https://www.consumer.ftc.gov/articles/0108-national-do-not-call-registry
Quote:Can I register my business phone number or a fax number?

The National Do Not Call Registry is only for personal phone numbers. Business-to-business calls and faxes are not covered.