Unauthorised debiting of my account a year later

Hi, I have ended business with Chubb in Aug 2014 after being a client (JA12592) for more than 13 years due to administration procedure inadequacy....(Armed response teams are quite efficient though). I had the radio transmitter removed in August 2014 by the Chubb tech, which Chubb claims only got removed in October 2014. Now, besides being called by their consultants every 2-3 months again asking for their radio transmitter (Clearly the head doesn't know what the tail is doing), I courteously explain the case to the unsuspecting consultant and just move on with life...until Sept 21, 2015. They bill me a year later for a SATRA licensing fee for a transmitter they removed and an additional amount I know nothing of. Is it to much to ask to be done with Chubb once and for all? Can they win back clients like me who dont easily change providers? Do I ever get refunded my money for a service they clearly did not provide? How many other people are having the same experience as me ....we will never know.