Money taken from my account

I tried one of these bitcoin traders and transfered money out of my account. The ***** line called and I allowed the transaction. Then they called again and spoke to my wife and told her that money had been bounced back into my account and she said as long as no more money was taken from the account. I checked my account and found money had not been returned but rather 4 more transactions of over R18000 had been taken from the account without my permission or knowledge. I have tried to call the FNB line repeatedly with no assistance, I have tried to WhatsApp chat as suggested with no assistance. I have even tried applying for a loan to cover the expenses that this money was supposed to pay without reply. I tried to call today and had the phone put down twice on me and was told once that no one was available to speak to me. I have been trying to get hold of FNB for over 3 to 4 weeks now to try get handled