My money is Missing and Nedbank does not want to assist me

I have a serious issue with Nedbank. On the 29 of July 2021 I made instant payment to someone and even today she has not received the money. 2days later I called their call center and I was told to give it two working days. A week passed and I called them again and they said they dont know what has happened because the account is correct and suggested I must go to my branch so they can check for me, I did and after spending 3hours in the branch no one could explain the whereabouts of my R1600. They said I must give them 48hrs and they will get back to me. Now its the 13th of August and all I am asking from them is the proof of payment because I can see on my status that the money left my account and the other party showed me her transactions she did not receive any amount from me. ...Please help