After 2 years with supersonic they want to charge me claw back fee

CANCELLED WITH SUPERSONIC AFTER 2 YEARS. Now after two years with them they want to charge a claw back fee. They sent me this info on email: 9.3 Month to month customers who decide to cancel will have to pay back a pro-rated amount for the router, connectivity and installation if they cancel within the first 12 months. They ignore all my mails when I ask why I was charged a claw back fee. Acc S4164 Spoke to '***' and '***' they have not bothered to answer me once...