Hi-Fi Corporation
Overpaid account, struggle to claim money

I overpaid my account. Called the call centre and they told me not to worry, "just go to any branch and they will refund you" is what they said.
I then went to the Boksburg branch on Tuesday.
They told me they do not have any funds available to refund me but will call me as soon as funds are available.
No phone call. Went back Wednesday, same story. No funds, but now I have to submit bank statements to proof I made the payment, although it shows on THEIR system that they owe me money.
Until today I have not received a call!!!