Bad service

I had deposit the money into a wrong account, I called FNB to information them I had to full in a form and I did. After awhile i got a response telling me that i should call the owner of the account (they client) and contact details was given. In my knowledge its not my due to call they client and even give me the clients details. I called the client and he advised me that he is no longer using the account. I call FNB and i was told they will look into and i have received any feedback. This was on the 20/02/2019.