OLD MUTUAL DOUBLE DEBITED MY ACCOUNT

Old mutual double debited my account. I called in to rectify the matter this morning however the call centre agent said I have to wait as its not reflecting on their system. Now I'm sitting with a return debit for my car finance due to the double debit that was done by old mutual. I contacted and insisted to speak with the manager however they refused to let me speak to the manager. Can this matter be resolved as R2700 has been deducted off my account. I am highly disappointed by old mutual finance and the level of service.