OLD MUTUAL IS WITHHOLDING CUSTOMER FUNDS

I have an investment account with Old mutual and a cheque account. I transfer money R1000 from the investment account to the cheque account for withdrawal. I went to go withdraw the R1000, only R600 came out. I tried to withdraw the R400, the machine said insufficient funds. I went inside, and I was told the ATM had issues, and it was fixed today(15/09/2021). I was informed that my money will reflect in my account later tonight (15/09/2021). The money is still not reflecting, and the SMS I received said I had withdrawn the R1000. I laid a formal complaint yesterday, and still, no one has gotten in touch with me. Old mutual just stole R400 from me, the primary job of a bank is to keep funds safe for the customer, instead OLD MUTUAL withholds the customer's money.