Unable to get Telkom to cancel unwanted service

I cancelled a service on 14-1-2020 with reference number ***5. The service should have been cancelled by Telkom at the end of February. Instead, Telkom cancelled a different service and the one cancelled remains and I continue to be billed. I cannot get through on the phone to the call center. I have sent multiple follow up emails on the cancellation request and although I get an automated response acknowledging receipt of the emails, I have had no response after weeks. I cannot dispute the invoices I am still bring debited for, as the app just reports an error. I tried canceling the service again; but the app just reports an error. I am desperate to get Telkom to cancel the correct service they were meant to cancel at the end of February and refund me for the invoices I continue to be sent for a service I don’t want and that should have been cancelled.