I was defrauded of the last 20K in my account

This unknown guy(09134941671 ) called me, saying he’s from FCMB, that they want to upgrade my account. I told him not to bother, that I will come to the bank to do it. Only for this guy to drop all my details fro me, from my full name to other account info to my BVN and finally my ATM card number. Not knowing he was a scammer, because no one should all know all these details asides me and my account manager, so he won my trust.
He told me read out OTP sent to me and I did it. This guy comot 20k+ from my account. He used my money to do online transaction. He only knew the digits on the front not the CVV at the back.