Fail to Cancel Contracts

I had a 2 year home wifi contract with telkom due to bad wifi connection i choose to cancel and choose a new provider. After sending the appropriate one month cancellation notice and received receipt for cancellation. Telkom continues to debit my account. I have send numerous mail communication. Followed the contact process on the website. I still have not heard from Telkom and i am continuing to loose money on a service which is cancelled for 3 months now.