Citibank complaint: Scam fraud

I received a text from citibank about a charge on my debit card. Asked if i made it and I said no. They said a fraud analyst would be calling me. They called and asked me questions about my card, if i had it or if anyone else had it. Then they asked about the last 5 transactions. I saw my acct online and they had them correct. Said my zelle acct was being used and they needed to prove my acct. Asked me about the only one transactions i had thru zelle and asked if i could call the one i sent to. I said i could not that i didnt have his number. They said they did and they were sending him a text for verification with a code.

He called me and when he asked what was up the bank rep said to him all we need is the code to verify. He gave them the code and 4999.94 came out of my acct and he hung up. I called the bank immediately and was told to file a diapute which i did. Then i get a ation from zelle asking if i authorized that payment and i said no. It was sent anyway and i denied it. The fraud dept denied my claim saying i authorized it. I did not . I tried to find the person it was sent to and there isnt any info on the name. I have filed 3 disputes and they wont return my money. I have been a 25 yr customer a nd i cant believe how unsafe they are.