One if you do not register your company as a foreign company you usually cannot file an answer in court if you are sued. 

I suggested using traps, and there were no further complaints until November 17.I promptly hired a professional for rodent treatment, which was completed within 10 days.The tenant is now demanding 3 months of free rent, claiming the property was "infected," despite my timely response and corrective measures.I need assistance crafting a response to this demand within 2 days to avoid escalation to small claims court.

You'll end up in court with a lease agreement that says rent is $1, and the recommended tip is $1,999.

We will see what the courts decide, just be aware of it. 

Section 8 can be a profitable and reliable resource but it is 'their ball, their court' so know the rules first.

If they refuse to help, then send them a demand letter through an attorney.If they still refuse to help, take them to court.

MA has a lot of courts, not a small state as you know.    

I'd go to Small Claims Court (<$7000. in MA).

Today, the injunction was struck down. Register your corporations by Jan 13, 2025

With nearly 400 units under management, I've only had to show up in court twice in ten years.