RCS won't refund me an erroneous payment (R11 057.00)

I erroneously paid R12 500.07 instead of R1 250 for my monthly instalment due on the 1st of August. It then turned out (via speaking with the call centre consultants) the instalment due was R1 443.05. I initially requested the refund of the difference (R11 057.00) on the 1st of August, 30min after the erroneous payment was made. I was then told I had to wait for the payment to reflect before anyone could refund me. I phoned again on Monday the 5th of August requesting the refund. I was told it would be done and would take a week. On the 12th August, I phoned again to follow up on the payment as it had not reflected on my account. I was told this would be done on Wednesday (14th August). On the 14th August, with no refund reflecting in my bank account I phoned again. After no luck, I phoned again on the 15th of August. This time a consultant requested my marriage certificate, as the new reason for refund not being paid is I emailed under my married name, and account in my ****en name. I sent through the requested documents and still, no payment has been made to-date (23rd August). I find this highly suspect, as I made a payment to clear my RCSLoan and required a refund as you debited me for the same amount and that refund was made in a matter of days, with no issues. I have spent over 3.5 HOURS on the phone to the call centre and every time I call I speak to a new clueless consultant and have to explain and be put on hold while they investigate or speak to their "manager". I have incurred thousands of rands in bank charges from this payment, that would not have been the case if the payment had been made the week of the 5th August, as originally assured.