Debit order not going through

My wife have been told that they can't debit her account for monthly instalments, this is despite the fact that funds have been available on the account, for the month of Jan - Feb we had to deposit the money into their Nedbank branch in Piet retief, MFC promised to fix and attend to the matter, again for the month of Feb-March the problem was still unresolved, they are now telling her that her account was handed over to the collectors, MFC is a ******* bank, if we knew we wouldn't have agreed to finance by then... Contact number for my wife: *** ZP Sibiya