Cancellation of service

I called Tracker to cancel on 30 November, I pay on the 1st for a month in advance. They told me I need to give a months notice but that I need to also pay for January. That is paying for two months! Why must I pay for two months if I am already paying for a month and giving a months notice? I had also phoned a week or so before to ask what the cancellation process was and no one informed me of the notice. They just told me to phone back when I sold my car and I could then \just"cancel. I also received terrible service from all the consultants I spoke to! """