Account not in arrears!!

After numerous uncollectable debit orders, I've arranged with MTN that I will pay my account by cash which I've paid each month. Now they blocked my account by saying I never paid my account. During this week I correspondent with their customer services (Ref SR#*** [#***]) and they've asked for proof of payments for two months (July and October) which they can't trace. Now all of sudden a debit order with my monthly account fee was collected from my bank account and now I'm asking who are giving them a right to collect a debit order from my account without my consent!! When I've spoken to their customer service, they've advised that they can't pay it back - how ridiculous. This is not my fault. Please sort out this **** because now as a customer of MTN I'm being treated unfairly after I've paid my account each month and MTN is not bringing their part by having their admin in place and reconsolidating their payments. Please pay my money back, as I won't have enough funds for the month due to this unplanned debit order!!