Stuck and no response

I payed for my holiday with my credit card and on the merchant side it said not received but from FNB they process the payment and the money went out of my account. Ive been trying to contact the cancellation and provided them with all the information they needed but to no response.

The merchant tried to help me as much as possible but FNB keeps sending me in circles. It takes forever to connect with chat on the app too and they close communications so fast (there is bad wifi here)

I had to make a double payment and FNB wont release the first payment even after merchant confirmed cancellation. I now have no money as had to double pay, I'm stuck on an island with no money because of the lack of assistance from FNB while they hold onto it.