Refund not being sorted since April 2015

I have been battling since April 2015 to get a refund for charges that have been debited to our credit card incorrectly. I have been phoning weekly to get the refund sorted out but nothing is happening.<br> On 25/3 an amount od R10380.00 was debited and then in May another 3 amounts of R5190.00. After so many phone calls it is now September and still no refund done. I have been told that the accounts and investigating department will sort it out and get back to me which has still not happened. They are very quick to debit your account incorrectly, but it is now taking months to get our refund back. What else do I HAVE TO DO?