Money Paid in wrong account. no positive respond

Old Mutual deposited the money in the wrong account number. when i opened the policy i was using STD Bank Savings account on 2005, Then now in 2015/10/29 i sent them my new banking details to Brenda Jansen, so the problem is when Kornita Jacobs makes the payment on the 2nd November 2015 he put in the old account. I phoned them they told me to ask the bank to reverse the money they told me they can not help as Old Mutual should correct it. After the bank i advised them that the bank failed to assist thats when Brenda as Kornita to correct it, i did the follow ups on the 16/11/2015 even today 17/11/15 but i dont see any way forward. please help I need that money.