Are you saying operable shutters that open and shut?

I've worked as a licensed athletic trainer, a maintenance technician for a local school/church, a package handler at FedEx Express, and I own and operate a small landscaping company. 

A lot of these folks pushing courses shut their flipping or wholesaling biz down years ago.

Just received an email from them notifying me that they are going to shut of the service in 10 days and they might need me to "provide the access to the property, if my tenants wouldn't cooperate."

You would need to be over the edge desperate to deal with the church, charity or refugees.

If they have no family or church to help them, they need to consider their reality.

If you can legally remove the door and frame the opening shut, you should be able to legally keep it locked.

(Their drapes were drawn and Venetian blinds closed shut. 

In NC if you register it and don't pay the fees, they will shut it down. 

But if you have a mean neighbor or a guest throws a beer can on someone elses lawn then your operation could get shut down and they will fine you.