Where did the money go?

I have a complaint about the Standard Bank branch in Potchefstroom. A client of mine paid R2400 through his FNB online account into a closed account of mine at Standard Bank. This Standard Bank account of mine was closed in June, and his payment was made on 6 July. The money was paid out of his account into the closed account, and I have been struggling to get this payment re-routed to my new Standard Bank account for more than a month now. I have been to the branch in Potchefstroom and has spoken to a lady called Cornelia. She told me Standard Bank cannot help me. If I am not mistaken, there is an account somewhere where misplaced funds are kept. Surely someone can find it there and pay it into my new account?! This is unacceptable. My client cannot solve this as the money has gone out of his account and has not been returned to him. I don't have the money, so Standard Bank has it somewhere and needs to solve this. I have all the details with regards to when the payment was made, the bank details of the transaction etc. Payment from: PJ Kleinhans Snr on 6 July at 08:42, to MM Basson, Standard Bank ********** 79 (closed during June already). I would appreciate it if somebody can fix this for me. My contact no is ********** 268.