BAD SERVICE FROM FNB CONSULTANT

I am a very unhappy customer has FNB has refused to reverse an online payment that was made by error into a wrong bank account which is capitec bank. FNB HAS STATED that a payment of R350 has to be paid but their is no guarantee that my amount of R1000 will be reversed to my account. What bad service I received from the FNB consultant stating that FNB won't reverse my online payment made in error.