Contract Cancellation

Requested a cancellation of a month to month contract early March 2014. then in December 2014 was handed over to Debtsource for debt collection and threat of Blacklist. Provided all communication to Debtsource including the contact person at ADT regarding the cancellation. Debtsource said that they would contact ADT to sort this out and would revert back to me with feedback. this did not happen, all I got was another sms in January telling me that I would be blacklisted if I did not pay the outstanding amount. I then contacted them again and got the same run around, I provided all the relevant info and they promised that they would get back to me, they did not respond to my follow ups or my emails. I have now received a 3rd threat of blacklist from Debtsource and ADT and I have still not had someone respond to my communications.