Mondo Telkom is ******** me

Mondo Telkom called me around May/June 2019 this year to offer me an upgrade on the contract I had with them. I agreed to the upgrade at first, they told me that if I want to cancel I have a week to do so and they gave me a contact number to use for cancellation . The following day after realising that I will not be able to afford the new contract, I called them and I canceled the contract. A few weeks after that I received a call from Mondo Telkom offering me an upgrade,I told them that I was not interested. After that I kept receiving these random calls from Mondo Telkom until I decided to stop answering because I was now feeling harsssed by Mondo Telkom. In August 2019, Telkom deducted R140 from my account, I reversed the debit order. This month ( September 13) again they deducted R412 from my account. I am still busy trying to stop the debit with my bank. Now I feel like I am dealing with ****s