+***0 this number called me on Friday

On Friday someone called me and said that he is calling from FNB and they want to reverse the money that was debited from my account, then he asked me if I'm still using my account then I told him that I'm afraid to use it, he asked me if I had another account I said yes then he asked me to give him the number at the back of my card so that he can link my account to pay me now I'm afraid maybe I'm going to be ****med I can't sleep I'm stressful.