PAYMENT REVERSAL GONE WRONG

I made an error on an account number when making a payment. I then opened a case with FNB. They closed the case saying they cannot get hold of the recipient and asked me to contact the recipient myself. I did so only to realise that the contact numbers given 1 belongs to someone else the 2nd one does not exist. The first number given the person who answered said I was trying to **** them. I feel FNB has not thoroughly done their investigations. What am I to do with just the customer name and wrong telephone numbers. What is the point of the KYC processes in banks if FNB cannot contact their customers.