My debit order goes ...

My debit order goes off every month (deducted by Telkom) and now on the 14th they suspended my account because I am, according to them, in arrears with R1!!! How ridiculous is this?? The bank charges to pay that is more!! And why am I at fault if I pay with debit order? I am for sure moving to a different service provider once my contract is up for renewal.. I was always happy with the service, but now... the customer care does not help.. only a sorry for the inconvenience and Telkom does not have an 'Accounts Department' to escalate it to. I am fed up!!!