Sick patient

Two weeks ago i went to garden city to obtain a receipt for tax purposes as i had lost the original od when i ws there last year march. When i got there i discovered that there was a credit of R1100.00 due to me that no one had informed me of. I am now told that i have to wait 7 to 14 days for the refund to be processed. I asked why i was never informed od the refund i was told that they only look at debit balances and call patients that owe them money. And that they don't look at credit balances and they dont inform patients of any monies due to them. Dont they get audited? Or rather who are their auditors?