Missing funds INSIDE the bank

So my mother deposits a lump some amount INSIDE the ATMs at nedbank in NU6 Mdantsane on Monday, assisted by one of the consultants. The money went in but "disappeared" and printed a receipt saying "sorry we cannot confirm your deposit due to technical error and your cash has been tetained". On Wednesday the 11th she received a reference number 580714 and still the money is not in. Now how safe are the clients at nedbank if these issues happen inside the bank and take a whole week to refund their own clients money? Why wait four days for management to actually approve money they can see in their system. This is the worst service from nedbank thus far!