FIRST NATIONAL BANK HAS GRAVELY DISSAPOINTED ME

I have been trying to stop a *****ulent transaction on my credit card account for about a week now. I was told that nothing can be done as the money had left my account EVEN THOUGH I ELECTED NOT TO APPROVE THE PAYMENT WHEN I RECEIVED THE PROMPT VIA MY BANKING APP. The payment was shown as a pending transaction at the time but I was told that it had already left my account even though I declined it. I was asked to log the matter as a case of *****, which I did. I was asked to cancel my credit card, which I did. The amount had stopped appearing on my pending or processed payments in my transaction history after i logged it as *****...until yesterday...where it's appeared as a pending transaction AGAIN. I called the ***** line again and was told that it's appearing because the "merchant" could not bank the money since it was the holidays...but they are doing so now... and that there is nothing more that i can do...as the money has left my account...?? Firstly...FNB...how does a payment get processed after I indicated that I DID NOT WANT TO APPROVE the transaction? Is the prompt that clients receive via their banking app warning them that they are about to make a transaction and requesting the client to approve or decline a payment, a useless prompt..or just a **** prompt....because the payment still went through and the money still left my account... even though it's showed up as a pending transaction TWICE ... Even though I've reported the matter a few minutes after it happening...and even though the "merchant" is only banking my money now (as per your ***** line feedback today)...nobody at FNB could do anything between the time i logged this matter, to yesterday where the "merchant" apparently had time to holiday and come back and still bank the money? I've been banking with FNB for 30 years... this is the most ridiculous thing I've had to experience with them...