Incorrect Billing Mont after Month

My account was closed on 12 December 2015 after I originally requested cancellation of the account on 7 October 2015. I am now battling to get the account finalized. Last month the account had a credit of R164.30 on the account and this month the account shows that I still owe Telkom R1278.25. Every month I am getting billed for services which was cancelled on the 12th of December 2015 already. This account was fully paid until the 12th of December 2015 when it was cancelled. Can this please be sorted out as I refuse to pay anything further on this account. My account number is: ***. Can someone please phone me to tell me what is going on.