Capitec not honouring debit orders

I am a customer for many years with Capitec but their service lately is driving me nuts. I have debit orders from my insurance and another creditor returning to them as "funds not provided for''. This is the second time this happens. July and now in September again. Although other debits go off some do not. Money also still available in my account. Not only is this reflecting extremely bad on my credit reputation but preventing me from doing future business with this companies. On the first instance I wrote to Capitec and asked for an explanation. They came back and said I have to take this up with my creditors. Why? They are not the ones refusing payment. Up till today I still do not have a satisfactory answer on this. I would like to warn people out there that Capitec do not care about you or your reputation. I will be waiting for them to answer this one.