Seriously disappointing service - Transaction reversal

On the 27 September I made a payment from my Credit Card into my Mothers account for the value of R2000. The transaction pended for a day then referenced as successful on my account and the funds were deducted. I later found the account number I paid the funds into was incorrect (actually not existent). I went into a branch in Fourways in an attempt to reverse the transaction (at a cost of close on R500). A couple of days later I received email correspondence explaining the account number I paid the funds into did not exist and requesting that I provide the correct account number. I rep**** to that, explaining once again what had happened to which I received no response. I requested feedback 5 days later to which they responded attaching the initial mail they sent me advising that the account number was invalid. As far as I'm aware, Nedbank should have first validated the account before successfully processing the transaction. No one can tell me what needs to happen or what I need to do to retrieve the cash. It cannot simply be paid into limbo and disappear. I could understand if the funds were paid into someone's account that refused to allow the cash to be refunded... but this... seriously disappointing service.