Direct debit after payment arrangement

I had a credit card with Nedbank but fell behind in payments. As a single mother it was difficult to keep up with the installments with the job I had. Finally I got a new job whereby I made arrangements with vh law to make monthly payments. But to my dismay Nedbank has debited my account of R7000. Even after the payment Arrangement. Thus is grossly ******* as the credit act says that one should pay what they are able to pay as long as payments are made. Nedbank tell me as a single mother how am I meant to pay for my daughters fees and rent if you debit my account if an amount like that. I'm reporting this act to the ombudsman as I think it is grossly unfair am ******* to put me out even though I'm meeting my payments. I need this sorted out ASAP Nedbank Ive bed with your bank for over 7 years bit this act will definitely make me move banks. I need that money refunded immediately. Can we please stick to the arrangement I made