Non payment of a refund

I was paying R500 towards my garage card account to settle the arrears of R3000. This was supposed to go for 6 months, but to my surprise the debit order carried on for the whole year. I went there to find out if I can be refunded the overpayment. Up to this date I haven't received any money from them. But they are very to deduct the money if I owe them. Is this fair?