Did you get the names of the techs that visited? Check ID? Call me paranoid, but it sounds fishy to me.
techs knock on doors all the time. either let them in, or you will get shut off.--I'm better than you!
But in my case they never knocked.@ harald, I understand what you're saying about the code issue. Comcast did it that way years ago. The house was made in the late sixties. Yes, the equipment is plugged into properly-grounded outlets.