*********** car track staff

I called in last year around February to change my tracking unit and I spoke to a lady that said they'll call me back. Which they didn't do. I called in again and told them since their service is so pathetic I want to cancel my contract with them since it was a month to month contract and I was told it was canceled. To my surprise they kept debiting my account and I'd reverse the debit. Then I get a call from a guy telling me that my car track is handed over, I then told the guy that my contract with car track was canceled long time ago, he then asked me to hold so he can check something and when he got back to me he said that there is a request for cancellation on my contract since last year but I'm surprised I got a letter of demand saying I need to pay a some amount of money. Your department's are so disorganized and I feel that I was assisted by *********** car track staff now I'm paying for their incompetency? My contract was cancelled long time ago