Not honouring payment holiday

I made payment holiday arrangements with Nedbank MFC for the months of May, June and July and to recommence payments from August. In May I received an sms from my bank saying that the debit order in respect of my vehicle finance with Nedbank MFC had not been honoured. I received another such sms in June. This means thay despite the payment arrangement Nedbank sent through debit order requests and my bank rejected them due to the obvious lack of funds. Now I probably have bank charges due to the unmet debit orders and also explains the nose dive in my credit score from the end of May. Who is now responsible for sorting out these bank charges and righting the defaults that get recorded on your credit record due to unmet debit orders. Very disappointed and annoyed!!!!