Extremely unprofessional and unhelpful

I did a international transfer over two weeks ago to my sister in law in the UK. The system gliched and I put the payment through twice by accident. I called immediately afterwards to cancel the payment. I was told it had been canceled and not to worry. The first payment came off that day. The following day the canceled payment was taken from my account with the bank charges. The recipient my sister in law recieved the first payment 2 days later. The 2nd payment that was supposed to be canceled she never received. I have had 2 weeks of absolute anguish worrying about where my money is. I have esculated it on numerous times. The only response I get from them is they waiting for the foreign bank to reply. 2 weeks and 2 days later. The money should never have left my account in the first place. It was canceled immediately and I got told from Standard bank this was done. All calls are recorded all the evidence is there. I sit out of pocket R13100 plus the bank charges over 2 weeks later with the same response everyday. Most emails get egnored and I sit on hold for long periods of time each day trying desperately to get my money back.