Cancelled Account still receiving statements

I took out a contract and was sent the wrong deal. In order for them to send me the correct one I first had to cancel the deal that was sent. After 5 long days and lots of calls and aggravation, I finally got the call to say it was cancelled. Due to the trouble and period it took to cancel I just thought it was not worth it and decided not to take another one. Anyway, I have now received a statement on the 15th January for a contract that was cancelled around the 14th December. PLEASE tell me how to cancel this for GOOD!!<br>