Account Cancelation

My contract with Telkom ended on the 12th December 2020. But they are still debiting my account. I reverse the debit order for them to just double the debit order the following month even triple it sometimes. I tried calling them and the phone rings nonstop. Went to their shop to cancel. They called the call centre on my behalf and then they said they were to call me back and they never did. I have done this several times. I decided to block my bank about 3 month later we are back to square one. They even double amounts if you revers payments. I just need to talk to Telkom. I turns out the Telkom shop can not do anything but just sell merchandise you can’t even pay for an account but to go to Pick n Pay to pay your account.