Telkom line and adsl cancelled but they are still billing me every month

My Telkom landline and adsl was cancelled by Telkom on 13 May 2018 after I have submitted a cancellation form giving 30 days notice, but their accounts department insists the service is still active and billed me up to 03 June 2018. I have made so many calls to 10210, but it's a total waste of time - they just tell me the line is still active! I went to the Alberton branch and still didn't get any help. Now I have received another bill for June - July rental and adsl. Please I cannot pay if my line was cancelled. 10210 and Alberton branch refuse to help. What can I do?