Help, FIAT withdrawal from OKX never arrived to my card

I have made a FIAT withdrawal of several hundreds of dollars the 26th of february and it never arrived on my card. I know I didn't make any mistake while inserting my bank account information because OKX verified it by making me do a deposit before I could withdraw any funds. I talked to customer service several times but they won't do anything because they say that they made the transaction and it was successful, so I should talk to my bank. I then talked to my bank but obviously they can't do anything about transactions that never arrived to them, so I'm stuck in this situation. I told the customer service that they should ask their bank to do an internal investigation to figure out what happened with the payment, but they keep refusing because according to them i have "successfully withdrawn the funds". They even asked me to send my account statement to prove that no funds arrived, but after I did that they still did nothing about it. How should I proceed?