FNB SHORT TERM LOAN SETTLEMENT FUNDS MISSING

I received a settlement letter to pay a short term loan with an account number I had to pay the money in to. My ID number to be used as reference. This settlement letter was sent via email and all instructions were followed as the money was being paid to FNB from another bank. I have all the proof. What should have been an immediate transaction - giving the weekend inbetween, never happenned. Follow up revealed that the account number I was given by FNB does not exist and the money should have bounced back into the bank account of origin. This did not happen. Can somebody please look into this as a matter of urgency and resolve it. What happenned to the money? I cannot afford that short term loan amount to be deducted when my salary is deposited on the 15th. The reference number of the query has been sent. I am really not a happy customer. Thank you.