Being charged for landline when cancelled

My mom's Telkom landline (account no.***) was cancelled on 23 June 2015 (***). She continued to receive bills where she was charged for her landline. After a couple of months, we phoned Telkom \Cancellations"who confirmed it was cancelled on the 23/6/2015 and put me through to \""Accounts\"". \""Accounts\"" denied it was cancelled and told me to call \""Cancellations\"". I was then told to fill in a Cancellation form on her behalf and to request to be back-paid. She signed it and provided a copy of her ID. I submitted this on 27 Nov 2015. There has been no feedback regarding her cancellation"