Double debit for online purchase

I am so frustrated with FNB right now! On the 24th of June 2020 I made an online purchase at Dischem, money was debited twice for the same transaction. The first time I attempted to pay the payment was declined, I tried again and it was successful, but money was debited for both attempts. I immediately called Dischem, they told me that only 1 payment went through on their side and they emailed me proof of this. I then contacted FNB using the secure chat on the app and was told that I needed to fill in a form and email it back to FNB, which I did and I attached the failed payment document from Dischem. I didn't receive an acknowledgement email or any communication from FNB so I sent the email again on the 27th of June 2020, I still didn't get any acknowledgement. On the 3rd of July 2020 I opened a chat on the app complaining about this and wanting to know what was going on, I received no help and was told to contact FNB by sending an email. I refused to send an email and asked for a phone number instead because sending an email appears to be useless. I called the number given to be me and I spoke to a gentlemen who said that he would send an email and that I must wait 48 hours for a response.. 48 hours has now passed and this morning I called FNB and was on the phone for almost an hour with a gentlemen who insisted that he could not see this payment that I am talking, he said he could only see one payment, not 2 payments of the same amount. I kept insisting that on my side I can see both, 1 was processed on the 27th of June and the other is still pending.. I eventually gave up, but he said he would launch an investigation into the matter.. Shortly after that a lady from FNB called me and I told her the same story and then she said she could see both amounts, but went on to ask if was I told that by claiming back my money using the forms I would be charged over R300, I was beyond shocked because with every single consultant that I spoke to, nobody cared to mention this and I REFUSE to be charged for a double debit that was not even my fault. I want my money back and I will not pay for this. I dont even understand why this process has been so difficult for me. I spend so much time on the secure chat only to be disconnected and reconnected to different consultants which means having to start my query from scratch. Then I spend hours on the phone with consultants who cant even help me. Hayi this is nonsense seriously!