She is putting on a sex show for OM in your house and you don't want to D her because of why?????? That is what you need to think about IMO you are far beyond dealing with WIFI issues.
She puts on a sex show for another man in your house with your kids in the house with the door locked and your response is to take away her WIFI? G-Dub.....that's not good.
So you take away the WIFI......can't she go sign up again? Does she have any money to pay that bill?