Canceled Contract being debited still

I got a broadband contract with Vodacom end 2018. On 11 March 2020 I called Vodacom and asked to cancel the contract prematurely as I was no longer in need of it. They sent me the invoice while as I was speaking to them over the phone.

On 13 March 2020 I sent all the documents and proof of payment to them as they requested.

Vodacom has still being debiting my account and sending me invoices. I have reached out on 12 June 2020 again but haven't any response to date. I understand the times that we are in.

Is there a ombudsman that can help me with this?

Not a honest company to deal with and is tremendously disappointed in their services.