Imcompetent and *********ly withholding Refund

Been paying off outstanding Life Groenkloof hospital account. Somehow they claim they did not receive proof of payment for 7 June 2019. I emailed c o l l e c t i o n s @ l c m 2 4 . c o . za to C h r i s t o J o u b e r t on 20 Aug requesting full outstanding balance to settle account only to pay the account but realize I overpayed. I put the very same email addr on the proof of payment but either it was a bank error that didn't send it or they just said they didn't get the proof to cover up the error. I immediately emailed C h r i s t o on 20 Aug to query this to which I received a ****y response saying if I sent the proof of payment as requested it wouldn't have happened. Also I should send my banking details for the refund and that the M.D D r V a n d e r M e r w e only does refunds once a month. Sent my bank details same day but alas no reply. Emailed again 26 Sept to follow up and yes you guessed it, no reply again. Yet again today I email still no reply. It is not about the amount to be refunded but my point is if I noted the Reference to them # 9 0 8 9 1 how did they still not find the payment on T H E I R bank statement. And what consequences would I face if I owed them and didn't pay. This behavior is *********** and so ********* to say the least. Next Step, complaint to the H P C S A if not rectified asap.