Apparently Customer Service Can't Help

So I had an incident with Sterns the other day which was sorted sort off thanks to the very helpful store manger at Sterns Festival Mall. But now I have to get a credit voucher from the store in order for my bank to refund my money. The store manager has confirmed 12 days ago that head office has confirmed that the money is not in their account but FNB needs this credit voucher in order for them to refund me. Now I am trying to call Sterns Festival Mall but there is no answer. So I call Sterns Head Office and this wonderful lady who didn't even give me her name and who is apparently a customer service supervisor can't help me. I asked that she contact Sterns Festival Mall as I can't get hold of them. She says she can't. Understandable. So I complain that the store doesn't answer. She says I need to go into the store then. I explain that I work and can't. Her answer is that she can't help me. Now, I am in customer service myself. I have been told to help customers as much as I can. If she is a supervisor and she isn't even prepared to help me as she herself said she can't help me (not even a suggestion on alternative numbers or area manger or anything like that - just "I can't help me" with attitude), then I would LOVE to have her job and do it 110 times better