Amount reserved for purchase

I tried making a purchase from iStore's website last night. Right after making the secure payment and the amount was reserved from my bank account, the website crashed. Once the website was working again I saw that my order was unsuccessful on iStore. However FNB did not reverse the reserved amount on their side. After having to contact FNB using their Secure Chat feature on the app, I was told by an agent that they could not do anything to help me and I would have to wait 7-14 days to get my back if iStore didnt debit the amount. The agent then also dismissed me as I tried to further discuss the issue. I now have to wait 7-14 days before I can make my purchase which actually an urgent purchase for me.