NorthStsar Alarm Services Refusal to cancel my contract El Paso Texas

I am making a formal complaint against NorthStar Alarm Services. On November 13,2017 I faxed (801) 373-4027 my written notice of cancellation of services nad also mailed them a hard copy, dated Feburay 23,2013 psrsgraph1. I on terms and conditions  signed  a sixty months contract. Customer has to give written notice of cancellation to the other at least 60 days prior to the end of any or initial or renewal term.

On November 13, 2017 I gave my written notice of cancellation more than the sixty days notification. I received a phone call two months after my notification  and cancellation that I was two months behind on my payments. I called back to NorthStar to talk with the person who had  contacted me  and was informed that this person was not there, but that the person I was talking with could help me, I tried to explain that  there was a mistake but he kept telling me I owed  two months back payments.

Again I proceded to  to explain that I had cancelled my contract, and was promptly hung up on. A week later Adam from NorthStar called and left a message saying that I owed two months back payments, so I called back and could not reach Adam, this person told me he could not help me because I could not recall my poassword from five years ago. I told them again that I had sent both a written and hard copy of my intention of csncelling. They refuse to honor my wishes and cancel my contract, but  continue to bombard me with calls that I  owe them for back payments.