Card dispute service of FNB!!!

I'm at my wits end with FNB Card Dispute Department. Since last year November and countless emails back and forth with them I can't get them to just do their part and refund me my money. I was online buying spectacles and when I tried paying and error came in. I had to redo the payment but when I did then it shows two payments had been made. I cancelled the first , disputed it and continued with my second order. There merchant then acknowledged the issue and paid me back my refund for the first order. To this day 26/01/2024 FNB have not restocked my issue and I'm stuck with following up for MY money after giving them all the proof they asked for even down to the card I used for the payment!! One of three agents an E Gouws even didn't bother to properly read my proof and assumed my refund was not agreed upon by the merchant and asked me again to send proof! I sent this proof last week Friday and today is Friday and no response still or any sign of them even doing anything to fix my issue!!! I then asked the merchant to confirm they indeed had made payment into my account and they sent proof. It's been all of January and still no response from FNB. So annoying and frustrating. I've been patient.