Failure to reverse payment

I deposited money into an incorrect standard bank account number on the 11 May 2015. I then sent an e-mail to my private banker Winnie Mgomezulu informing her about the error, with no response from her at the time I went to FNB at OR Tambo airport at around 8pm and the lady at customer services confirmed that the account numbers I used had 10 digits and Standard Bank account number has only 9 digits and the money will bounce back into my account within 48 hours. On the 12 May I received reversal forms from the Winnie and I did not complete them since I had confirmation from FNB OR Tambo. 48 hours later no money in my account, I then completed the forms and sent them back to Winnie on the 15 May 2015. On the 18 May I received an email from FNB saying the money cannot be reversed and I then went to standard bank where they confirmed that the account number I used does exist and they cannot reveal third party information to me, but to FNB only. Standard bank also confirmed that only FNB can do the reversal and to date I received no help from FNB. I phoned customer care on the 25 and they gave me ref no 689857 and till today I received nothing from FNB. I suspect this is an inside job.