delay in reversing EFT

Had money eft to me but by accident I gave them my old savings account number and not my cheque account. Only after the money went through did I realise my mistake. Went to the bank and was told my old savings account was reissued to someone else. They tried to phone but could not get through. I was then told to tell the depositor to phone his bank which he did to do a recall. Now we told it will take up to 6 weeks just for an answer only. Not a guaranteed reversal of funds. I find this unexceptable time to wait and also why was I never told my old account is reused. If Standard Bank just closed account I could have excepted that but to give it to a new client without my knowledge is unexceptable. If you never did this we would have had the money returned in 2 weeks no problems. Get this done faster or Im taking it further ..Ombudsman.