Been trying to cancel month to month LTE subscription since DECEMBER! Contract ended long ago

Cancellation of LTE contract after 2 year contract ran out and service not required.

I have been trying to cancel this contract since December last year. I went onto the month to month option after I ran out my 2 year contract, because I had a tenant in my flat until end February. I tried the call center, I tried the Telkom shop, I filled in the forms they gave me, I emailed it to the right address. NOTHING has happened. And, as you can imagine, today the debit order went off. The form was sent ages ago. In December a call center salesman even told me over the phone he has logged the cancellation for end February. I phone the Telkom customer support center, and they said that it is impossible that this could have happened, since one can only cancel in store. So I went to the store, and here I was told it is only possible to cancel by filling in the cancellation forms and emailing it to the email provided.

I am still paying! I cancelled it for end of February! I cancelled it in advance. I want my full refund with interest. ASAP.