refusal to cancell expired contract

my cell phone contract expired on the 4/10/15. I called in to speak to an agent who advised me to send an email to the retention department. I did, and received reference number ***5. after some time I called in to confirm that they will not debit my account only to find out that they haven't cancelled my contract even though it expired on the 4/10/15. I spoke to refilwe mogale on the 20/10/15. sent another email. however still no luck.on the 2 /11/15 debit order still been deducted.i emailed retentions department again , no feedback. I sent another email. nothing. I called in again on 4/12/15 as still debit order been deducted. spoke to dimakso barbarian who said sorry she will send an email again. I asked to speak to her line manager, no luck the manager refused to speak to me saying that she must send an email. I send another email. again I call in speak to lucky selepe who advised me to keep on calling and ask which call centre im speaking to as he cannot transfer me but if im lucky to get through to 14th avenue then they will transfer me. this is pathetic. I have 3 contracts with mtn and I will ensure that I never upgrade my contracts with them if they are *****ing from me