SAPO or Postbank

I have benn to Benmore Post Office to escalate a SASA grant system error in payment. I have been trying to get payment of 6 months in arrears at the Benmore Gardens post office, since the 17th December. They have told me that they tried to call the Postbank call centre to get them to reverse the transaction do they can redo the transaction. I have turned back; again today. I have once again been told they have been trying Postbank and will call me. Confusing, frustrating and disappointing service.