No response after several emails and phone calls

I have made an online purchase on 19 December with my FNB visa card and the money was deducted from my account. The company that I bought the items from required that I authorize the payment and that I have to contact my bank in order to do so. I have sent several emails to FNB ********** since I am not in the country and international calls are very expensive.

I have had zero response from my emails therefore I have made one international phone call that have cost me over R200 just to be transferred from department to department for over 50 minutes. Some departments had no pick-up on a 24 hour call centre. This lead to no success.

I would appreciate if this request can be resolved in a positive and timely manor.