Handover by Neotel to NuDebt for amount not due.

After a storm in July/August last year I had no service on my month to month contract with Neotel which had expired 16/05/2016.After many attempts to resolve this at their Umhlanga Crescent Service Center, to no avail , I cancelled my contact on 9 September 2016. i.e. I had had no service by now for about 6 weeks. I received a cancellation reference number from CS Retentions. Neotel debited me again, the debit of which, I had reversed by the bank. Neotel without discussion, immediately handed me over to NuDebt. They had not app**** their minds. My contention is that I should have been refunded my August debit due to no service. Their response was that, debit order cancellations take 3 weeks to implement. That means I must pay for no service, and their turnaround time. Despite verbal and written correspondence to NuDebt they have ignored my correspondence and continued to harass me via SMS. They have now listed me with a credit bureau. How many people are bul**** into submission like this. In my case the amount is R182.64, Their Ref: ND ********** 6. Please help