Cancellation of a data bundle

I canceled a data bandle at a Telkom brance on 26.11.17. I was informed that there will be an installment still going off in Desember 2017. We are in March already and they are still deducting the installment from my account. I went in last month to solve the problem and then they couldn’t find the cancelation on the system but it was sent through by the Telkom branch where I canceled it. I went to reverse the debit order cause nobody could help me. After I reveres the payment i went to the store to cancel my debit order and again they said that will not be possible. So they did a immediate cancelation on my data bundle but also couldn’t give me any answers on the money they been deducting for the past 2 months. This month the money was again decucted and the balance of the money I reversed the previous month plus R200 extra for the debit order that didn’t went through. Now I don’t know who can help me because nobody at Telkom can help me and i will not pay any extra costs for a fault on Telkoms side and how can Telkom not cancel a debit order on request??