Still getting billed for an account that was cancelled on 27 June 2017

I am still getting billed for a telephone line which has been cancelled on the 27th June 2017. I still paid for July which formed part of my 30 day notice month. Then in August my account again got debited again. I phoned Telkom and a very nice lady assisted me, said the forms were received but the debit order was not stopped. So she rectified the issue, she also logged a grievance on my behalf to reverse the debit order from August. Then in last week another debit order went off my account, luckily ABSA as a reverse debit order feature which I used twice now. I will not pay any arrears on this account as all necessary steps were followed to get the line cancelled.