Money deducted thrice off credit card account

I made a credit card purchase on Friday, the money came off as usual and got the confirmation email from the merchant. I then received notifications a few hours later stating that I have insufficient funds, as the same transaction went off for the third time and failed on the third time due to insufficient funds. I called FNB and was told that they were having a technical issue and that I will get my money back by the next day for trying to take the money off thrice. The next day I called, and still no luck, I was told that the issue was not resolved. Ref: RV ********** 6171. I then called again today (sunday) and was first put on hold by Shanil Bhurath for so long just to view my account. (Ref: RY ********** 474) I then hung up and called again and spoke to Zandile ref:RC ********** 777 who told me that this is now a merchant issue. So I had to keep on calling and calling and being told that its a fnb system error, while nobody notifies me to contact the merchant as this is where they now believe the problem lies. I had asked Zandile to get a manager to call me to address this issue. Im still waiting for the call. This is highly frustrating for money to be coming off for no reason.