Ace is operated by OK Rent a Car But they really work as separate companies and the OK employees want nothing to do with Ace problems. Which is what happened to me. I had a reservation with Ace that had to be paid with a credit card (not flagged by any of the emails). I have AMEX credit card. But OK did not want to take AMEX, and wouldn’t take any of my debit cards. After a long and stressful discussion (1 hour !!! after I entered the pickup booth) the situation was resolved with a financial penalty at a higher cost than originally contracted. The OK guys, at first defensive and denying any wrongdoing on their part, ended up understanding and trying to help, at a cost.